diff --git a/application/single_app/requirements.txt b/application/single_app/requirements.txt
index ceff7d77a..4ed0f99dd 100644
--- a/application/single_app/requirements.txt
+++ b/application/single_app/requirements.txt
@@ -64,6 +64,8 @@ psycopg2-binary==2.9.10
 cython==3.2.4
 pyyaml==6.0.2
 aiohttp==3.14.3
+# AnyIO 4.11+ requires typing_extensions.sentinel, which older App Service agents can shadow.
+anyio==4.10.0
 html2text==2025.4.15
 matplotlib==3.10.7
 azure-cognitiveservices-speech==1.48.2
diff --git a/application/single_app/route_backend_conversations.py b/application/single_app/route_backend_conversations.py
index 476356249..440077665 100644
--- a/application/single_app/route_backend_conversations.py
+++ b/application/single_app/route_backend_conversations.py
@@ -237,6 +237,41 @@ def _build_replayed_document_context(original_metadata):
         'active_public_workspace_ids': workspace_search.get('active_public_workspace_ids') or [],
     }
 
+def _build_replayed_model_context(original_metadata, request_data=None):
+    """Rebuild model endpoint routing from stored metadata for retry and edit."""
+    metadata = original_metadata if isinstance(original_metadata, dict) else {}
+    model_selection = metadata.get('model_selection')
+    model_selection = model_selection if isinstance(model_selection, dict) else {}
+    request_data = request_data if isinstance(request_data, dict) else {}
+
+    stored_request_model = str(
+        model_selection.get('frontend_requested_model')
+        or model_selection.get('selected_model')
+        or ''
+    ).strip()
+    stored_selected_model = str(model_selection.get('selected_model') or '').strip()
+    requested_model = str(request_data.get('model') or '').strip()
+    replayed_model = requested_model or stored_request_model
+    reuses_stored_selection = not requested_model or requested_model in {
+        stored_request_model,
+        stored_selected_model,
+    }
+
+    def requested_or_stored(request_key, metadata_key):
+        requested_value = request_data.get(request_key)
+        if requested_value not in (None, ''):
+            return requested_value
+        if reuses_stored_selection:
+            return model_selection.get(metadata_key)
+        return None
+
+    return {
+        'model_deployment': replayed_model or None,
+        'model_id': requested_or_stored('model_id', 'model_id'),
+        'model_endpoint_id': requested_or_stored('model_endpoint_id', 'model_endpoint_id'),
+        'model_provider': requested_or_stored('model_provider', 'model_provider'),
+        'model_icon': requested_or_stored('model_icon', 'model_icon'),
+    }
 
 def _get_requested_workspace_document_delete_ids_for_conversation(payload, conversation_id):
     if not isinstance(payload, dict):
@@ -2758,7 +2793,6 @@ def retry_message(message_id):
         
         try:
             data = request.get_json() or {}
-            selected_model = data.get('model')
             reasoning_effort = data.get('reasoning_effort')
             agent_info = data.get('agent_info')  # Get agent info if provided
             
@@ -2915,10 +2949,11 @@ def retry_message(message_id):
             )
             # Build chat request parameters from original message metadata
             replayed_document_context = _build_replayed_document_context(original_metadata)
+            replayed_model_context = _build_replayed_model_context(original_metadata, data)
             chat_request = {
                 'message': user_content,
                 'conversation_id': conversation_id,
-                'model_deployment': selected_model or original_metadata.get('model_selection', {}).get('selected_model'),
+                **replayed_model_context,
                 'reasoning_effort': reasoning_effort or original_metadata.get('reasoning_effort'),
                 **replayed_document_context,
                 'image_generation': original_metadata.get('image_generation', {}).get('enabled', False),
@@ -3139,10 +3174,11 @@ def edit_message(message_id):
             # Build chat request parameters from original message metadata
             # Keep all original settings (model, reasoning, doc search, etc.)
             replayed_document_context = _build_replayed_document_context(original_metadata)
+            replayed_model_context = _build_replayed_model_context(original_metadata)
             chat_request = {
                 'message': edited_content,  # Use edited content
                 'conversation_id': conversation_id,
-                'model_deployment': original_metadata.get('model_selection', {}).get('selected_model'),
+                **replayed_model_context,
                 'reasoning_effort': original_metadata.get('reasoning_effort'),
                 **replayed_document_context,
                 'image_generation': original_metadata.get('image_generation', {}).get('enabled', False),
diff --git a/application/single_app/route_backend_retention_policy.py b/application/single_app/route_backend_retention_policy.py
index 6384760bb..6779daf17 100644
--- a/application/single_app/route_backend_retention_policy.py
+++ b/application/single_app/route_backend_retention_policy.py
@@ -410,7 +410,7 @@ def update_user_retention_settings():
             # Validate and parse conversation retention
             if 'conversation_retention_days' in data:
                 conv_retention = data['conversation_retention_days']
-                if conv_retention == 'none' or conv_retention is None:
+                if conv_retention == 'none' or conv_retention == 'default' or conv_retention is None:
                     retention_settings['conversation_retention_days'] = 'none'
                 else:
                     try:
@@ -435,7 +435,7 @@ def update_user_retention_settings():
             # Validate and parse document retention
             if 'document_retention_days' in data:
                 doc_retention = data['document_retention_days']
-                if doc_retention == 'none' or doc_retention is None:
+                if doc_retention == 'none' or doc_retention == 'default' or doc_retention is None:
                     retention_settings['document_retention_days'] = 'none'
                 else:
                     try:
@@ -519,7 +519,7 @@ def update_group_retention_settings(group_id):
             # Validate and parse conversation retention
             if 'conversation_retention_days' in data:
                 conv_retention = data['conversation_retention_days']
-                if conv_retention == 'none' or conv_retention is None:
+                if conv_retention == 'none' or conv_retention == 'default' or conv_retention is None:
                     retention_settings['conversation_retention_days'] = 'none'
                 else:
                     try:
@@ -544,7 +544,7 @@ def update_group_retention_settings(group_id):
             # Validate and parse document retention
             if 'document_retention_days' in data:
                 doc_retention = data['document_retention_days']
-                if doc_retention == 'none' or doc_retention is None:
+                if doc_retention == 'none' or doc_retention == 'default' or doc_retention is None:
                     retention_settings['document_retention_days'] = 'none'
                 else:
                     try:
@@ -629,7 +629,7 @@ def update_public_workspace_retention_settings(public_workspace_id):
             # Validate and parse conversation retention
             if 'conversation_retention_days' in data:
                 conv_retention = data['conversation_retention_days']
-                if conv_retention == 'none' or conv_retention is None:
+                if conv_retention == 'none' or conv_retention == 'default' or conv_retention is None:
                     retention_settings['conversation_retention_days'] = 'none'
                 else:
                     try:
@@ -654,7 +654,7 @@ def update_public_workspace_retention_settings(public_workspace_id):
             # Validate and parse document retention
             if 'document_retention_days' in data:
                 doc_retention = data['document_retention_days']
-                if doc_retention == 'none' or doc_retention is None:
+                if doc_retention == 'none' or doc_retention == 'default' or doc_retention is None:
                     retention_settings['document_retention_days'] = 'none'
                 else:
                     try:
diff --git a/application/single_app/static/css/styles.css b/application/single_app/static/css/styles.css
index 611092e26..ef2643874 100644
--- a/application/single_app/static/css/styles.css
+++ b/application/single_app/static/css/styles.css
@@ -124,18 +124,21 @@ main {
     color: #e9ecef !important;
 }
 
-/* Fix for group dropdown in dark mode */
-[data-bs-theme="dark"] #group-dropdown .group-search-container {
+/* Fix for workspace selector dropdowns in dark mode */
+[data-bs-theme="dark"] #group-dropdown .group-search-container,
+[data-bs-theme="dark"] #public-dropdown .public-search-container {
     background-color: #343a40 !important;
     border-bottom: 1px solid #495057 !important;
 }
 
-[data-bs-theme="dark"] #group-dropdown .dropdown-item:hover {
+[data-bs-theme="dark"] #group-dropdown .dropdown-item:hover,
+[data-bs-theme="dark"] #public-dropdown .dropdown-item:hover {
     background-color: #495057 !important;
     color: #e9ecef !important;
 }
 
-[data-bs-theme="dark"] #group-dropdown .dropdown-menu {
+[data-bs-theme="dark"] #group-dropdown .dropdown-menu,
+[data-bs-theme="dark"] #public-dropdown .dropdown-menu {
     background-color: #343a40 !important;
     color: #e9ecef !important;
     border-color: #495057 !important;
diff --git a/application/single_app/static/js/chat/chat-input-actions.js b/application/single_app/static/js/chat/chat-input-actions.js
index bc8c9d830..517be4d33 100644
--- a/application/single_app/static/js/chat/chat-input-actions.js
+++ b/application/single_app/static/js/chat/chat-input-actions.js
@@ -303,6 +303,18 @@ function buildUploadFileList(filesLike, fallbackPrefix = "clipboard_upload") {
     .filter(Boolean);
 }
 
+async function ensureUploadFileIsReadable(file) {
+  const fileName = String(file?.name || "selected file").trim() || "selected file";
+
+  try {
+    await file.slice(0, Math.min(file.size, 1)).arrayBuffer();
+  } catch (error) {
+    throw new Error(
+      `The browser could not read "${fileName}". Close the file in other apps then try again.`
+    );
+  }
+}
+
 function hasNamedFile(files) {
   return Array.from(files || []).some((file) => String(file?.name || "").trim());
 }
@@ -684,6 +696,7 @@ export async function uploadFileToConversation(file) {
   let uploadingIndicatorEl = null;
 
   try {
+    await ensureUploadFileIsReadable(file);
     const groupUploadContext = await resolveGroupUploadContext();
     uploadingIndicatorEl = showFileUploadingMessage();
 
@@ -706,10 +719,18 @@ export async function uploadFileToConversation(file) {
       });
     }
 
-    const response = await fetch("/upload", {
-      method: "POST",
-      body: formData,
-    });
+    let response;
+    try {
+      response = await fetch("/upload", {
+        method: "POST",
+        body: formData,
+      });
+    } catch (error) {
+      const fileName = String(file?.name || "selected file").trim() || "selected file";
+      throw new Error(
+        `The browser could not upload "${fileName}". The file may be open in another app, unavailable from cloud storage, or the network connection may have been interrupted. Ensure the file is closed and then try again.`
+      );
+    }
 
     hideFileUploadingMessage(uploadingIndicatorEl);
     uploadingIndicatorEl = null;
diff --git a/application/single_app/static/js/chat/chat-retry.js b/application/single_app/static/js/chat/chat-retry.js
index 99d3cfdf3..be2612b05 100644
--- a/application/single_app/static/js/chat/chat-retry.js
+++ b/application/single_app/static/js/chat/chat-retry.js
@@ -102,7 +102,8 @@ export async function handleRetryButtonClick(messageDiv, messageId, messageType)
     
     if (modelSelect && retryModelSelect) {
         // Clone model options from main select
-        retryModelSelect.innerHTML = modelSelect.innerHTML;
+        const clonedOptions = Array.from(modelSelect.options || []).map((option) => option.cloneNode(true));
+        retryModelSelect.replaceChildren(...clonedOptions);
         retryModelSelect.value = modelSelect.value; // Set to currently selected model
     }
     
@@ -188,14 +189,26 @@ export async function handleRetryButtonClick(messageDiv, messageId, messageType)
                 levels.forEach(level => {
                     const div = document.createElement('div');
                     div.className = 'form-check';
-                    div.innerHTML = `
-                        <input class="form-check-input" type="radio" name="retry-reasoning-effort" 
-                               id="retry-reasoning-${level.value}" value="${level.value}" 
-                               ${level.value === 'medium' ? 'checked' : ''}>
-                        <label class="form-check-label" for="retry-reasoning-${level.value}">
-                            <strong>${level.label}</strong> - ${level.description}
-                        </label>
-                    `;
+
+                    const input = document.createElement('input');
+                    input.className = 'form-check-input';
+                    input.type = 'radio';
+                    input.name = 'retry-reasoning-effort';
+                    input.id = `retry-reasoning-${level.value}`;
+                    input.value = level.value;
+                    input.checked = level.value === 'medium';
+
+                    const label = document.createElement('label');
+                    label.className = 'form-check-label';
+                    label.setAttribute('for', input.id);
+
+                    const strong = document.createElement('strong');
+                    strong.textContent = level.label;
+
+                    label.appendChild(strong);
+                    label.appendChild(document.createTextNode(` - ${level.description}`));
+                    div.appendChild(input);
+                    div.appendChild(label);
                     retryReasoningLevels.appendChild(div);
                 });
             }
@@ -264,8 +277,18 @@ window.executeMessageRetry = function() {
         // Model mode - get model and reasoning effort
         const retryModelSelect = document.getElementById('retry-model-select');
         const selectedOption = retryModelSelect ? retryModelSelect.options[retryModelSelect.selectedIndex] : null;
-        const selectedModel = selectedOption?.dataset?.deploymentName || (retryModelSelect ? retryModelSelect.value : null);
+        const selectedModel = selectedOption?.dataset?.requestModel
+            || selectedOption?.dataset?.deploymentName
+            || (retryModelSelect ? retryModelSelect.value : null);
         requestBody.model = selectedModel;
+        requestBody.model_id = selectedOption?.dataset?.modelId || null;
+        requestBody.model_endpoint_id = selectedOption?.dataset?.endpointId || null;
+        requestBody.model_provider = selectedOption?.dataset?.provider || null;
+        try {
+            requestBody.model_icon = JSON.parse(selectedOption?.dataset?.modelIcon || '{}');
+        } catch (error) {
+            requestBody.model_icon = {};
+        }
         
         let reasoningEffort = null;
         const retryReasoningContainer = document.getElementById('retry-reasoning-container');
diff --git a/application/single_app/templates/public_workspaces.html b/application/single_app/templates/public_workspaces.html
index ac3864f6b..979ec94f3 100644
--- a/application/single_app/templates/public_workspaces.html
+++ b/application/single_app/templates/public_workspaces.html
@@ -213,7 +213,7 @@ <h3 id="active-public-name" style="display:none"></h3>
 
   {% include "_semantic_search_health_warning.html" %}
 
-  <div class="row mb-3 align-items-center g-2" id="public-selector-row">
+  <div class="row mb-3 align-items-center g-2 workspace-toolbar-row" id="public-selector-row">
     <div class="col-12 col-lg">
       <div class="dropdown" id="public-dropdown">
         <button class="form-select d-flex justify-content-between align-items-center" id="public-dropdown-button" data-bs-toggle="dropdown">
diff --git a/docs/explanation/fixes/CHAT_RETRY_EDIT_MODEL_ENDPOINT_REPLAY_FIX.md b/docs/explanation/fixes/CHAT_RETRY_EDIT_MODEL_ENDPOINT_REPLAY_FIX.md
new file mode 100644
index 000000000..3843adf50
--- /dev/null
+++ b/docs/explanation/fixes/CHAT_RETRY_EDIT_MODEL_ENDPOINT_REPLAY_FIX.md
@@ -0,0 +1,37 @@
+# Chat Retry and Edit Model Endpoint Replay Fix
+
+Retrying a response or editing a prompt could fail before receiving content even though the original request succeeded. The replay request restored only the saved model name, so multi-endpoint models could be sent to the default Azure OpenAI resource instead of the endpoint that handled the original request.
+
+Fixed/Implemented in version: **0.261.033**
+
+Related config.py update: `VERSION = "0.261.033"`
+
+## Root Cause
+
+Initial chat sends include the request model, model ID, endpoint ID, and provider. Retry and edit preparation rebuilt `model_deployment` from `metadata.model_selection.selected_model` but discarded the other routing fields. Without `model_endpoint_id`, streaming model resolution could fall through to the default Azure OpenAI client and use a model identifier as an Azure deployment name, resulting in `DeploymentNotFound`.
+
+## Technical Details
+
+Files modified:
+
+- `application/single_app/route_backend_conversations.py`
+- `application/single_app/static/js/chat/chat-retry.js`
+- `functional_tests/test_chat_retry_edit_model_endpoint_replay.py`
+- `application/single_app/config.py`
+
+The backend now rebuilds the complete model routing context from the original message metadata for retry and edit. The retry modal also sends the selected option's request model, model ID, endpoint ID, provider, and icon, matching the initial chat request contract. A retry that explicitly selects another model does not inherit stale endpoint metadata.
+
+## Validation
+
+Regression coverage verifies that:
+
+- Edit restores the original request model and endpoint identity.
+- Retrying the same model preserves the saved endpoint identity.
+- Selecting a different model does not retain stale endpoint fields.
+- The retry frontend sends the complete selected model identity.
+
+The Python route compiles successfully and the retry JavaScript passes `node --check`.
+
+## Impact
+
+Retry and edit requests for multi-endpoint models are routed to the same configured endpoint as the original response, avoiding false Azure OpenAI `DeploymentNotFound` failures before streaming begins.
\ No newline at end of file
diff --git a/docs/explanation/fixes/CHAT_UPLOAD_FILE_ACCESS_ERROR_FIX.md b/docs/explanation/fixes/CHAT_UPLOAD_FILE_ACCESS_ERROR_FIX.md
new file mode 100644
index 000000000..58e53cc73
--- /dev/null
+++ b/docs/explanation/fixes/CHAT_UPLOAD_FILE_ACCESS_ERROR_FIX.md
@@ -0,0 +1,39 @@
+# Chat Upload File Access Error Fix
+
+Fixed in version: **0.261.032**
+
+## Issue
+
+Dragging a file into chat could report only `Failed to fetch` when the browser
+could not read the file. This commonly affected cloud-synced documents that
+were open in another application or were not fully available on the device.
+Because the browser failed while preparing the request body, the upload never
+reached SimpleChat and no corresponding server log entry was created.
+
+## Root Cause
+
+The chat uploader passed the selected `File` directly to `fetch()`. Browser
+file-access failures surfaced as a generic network `TypeError`, which did not
+identify the document or explain how the user could resolve the problem.
+
+## Technical Details
+
+The shared chat upload path now performs a minimal file-read check before
+starting the request. If that check fails, the toast identifies the filename
+and asks the user to close it in other applications or make it available
+offline. A later browser transport failure also explains the possible file
+lock, cloud availability, and network causes instead of displaying only the
+opaque browser error.
+
+The change applies consistently to files selected with the paperclip, pasted
+from the clipboard, or dropped into the chat input.
+
+## Validation
+
+The existing chat upload Playwright workflow now simulates an unreadable
+dropped file and verifies that the actionable toast appears without an upload
+request. Functional coverage also checks that the shared uploader retains the
+file-read guard and recovery guidance.
+
+The application version in `application/single_app/config.py` was updated to
+`0.261.032` for this fix.
\ No newline at end of file
diff --git a/docs/explanation/release_notes.md b/docs/explanation/release_notes.md
index 453c5224e..fa1093ec9 100644
--- a/docs/explanation/release_notes.md
+++ b/docs/explanation/release_notes.md
@@ -6,6 +6,21 @@ For feature-focused and fix-focused drill-downs by version, see [Features by Ver
 
 #### Bug Fixes
 
+*   **Chat Upload File Access Errors Avoid Browser-Realm Checks**
+    *   Hardened chat upload recovery messaging so rejected browser upload requests no longer depend on a realm-specific `TypeError` check.
+    *   Fetch preparation and transport failures now consistently identify the selected file and show the same recovery guidance for locked files, cloud-placeholder files, and interrupted local upload requests.
+    *   Also removed unsafe HTML-string construction from the retry modal's model-option cloning and reasoning-level controls.
+    *   (Ref: chat upload file access handling, retry modal rendering, `chat-input-actions.js`, `chat-retry.js`, `test_chat_clipboard_paste_upload_support.py`)
+
+### **(v0.261.045)**
+
+#### Bug Fixes
+
+*   **Public Workspace Selector Dark Theme Styling**
+    *   Fixed the public workspace selector dropdown so its dark-theme background, border, search area, hover state, and active item styling match the group workspace selector.
+    *   Added the shared workspace selector row class to the public selector row and extended the existing group dropdown dark-theme rules to the public dropdown.
+    *   (Ref: public workspace selector, dark theme dropdown styling, `public_workspaces.html`, `styles.css`)
+
 *   **Revert Premature OneNote Rollout From Development**
     *   Removed native `.one` and `.onepkg` workspace uploads from Development pending Reactv2 testing, correcting the accidental merge of PR #1525.
     *   Restored the previous upload formats and container packaging. Existing document formats and the separately adapted Reactv2 OneNote implementation remain unchanged.
diff --git a/functional_tests/test_chat_clipboard_paste_upload_support.py b/functional_tests/test_chat_clipboard_paste_upload_support.py
index c3eac9c8b..e0a2cf84a 100644
--- a/functional_tests/test_chat_clipboard_paste_upload_support.py
+++ b/functional_tests/test_chat_clipboard_paste_upload_support.py
@@ -2,15 +2,17 @@
 #!/usr/bin/env python3
 """
 Functional test for chat clipboard paste upload support.
-Version: 0.241.056
-Implemented in: 0.241.056
+Version: 0.261.046
+Implemented in: 0.241.056; expanded in: 0.261.032; hardened in: 0.261.046
 
 This test ensures chat paste uploads route clipboard files through the shared
 chat upload helper, normalize missing clipboard filenames, preserve normal text
-paste behavior after image uploads, and support dropped files in the chat input.
+paste behavior after image uploads, support dropped files in the chat input,
+and provide actionable errors when the browser cannot read an upload.
 """
 
 import os
+import re
 import sys
 from test_support.versioning import assert_app_version_at_least
 
@@ -115,12 +117,40 @@ def test_chat_drag_and_drop_upload_binding():
     print("✅ Chat drag-and-drop upload binding passed")
 
 
+def test_chat_upload_reports_unreadable_files_with_recovery_guidance():
+    """Verify local file access failures identify the document and recovery steps."""
+    print("🔍 Testing unreadable chat upload guidance...")
+
+    content = read_file(CHAT_INPUT_ACTIONS_FILE)
+
+    required_snippets = [
+        "async function ensureUploadFileIsReadable(file) {",
+        "await file.slice(0, Math.min(file.size, 1)).arrayBuffer();",
+        "await ensureUploadFileIsReadable(file);",
+        'The browser could not read "${fileName}".',
+        "Close the file in other apps then try again.",
+        'The browser could not upload "${fileName}".',
+        "The file may be open in another app, unavailable from cloud storage, or the network connection may have been interrupted.",
+    ]
+
+    missing = [snippet for snippet in required_snippets if snippet not in content]
+    assert not missing, f"Missing unreadable upload guidance snippets: {missing}"
+    assert re.search(
+        r"catch \(error\) \{\s*const fileName = String\(file\?\.name \|\| \"selected file\"\)\.trim\(\) \|\| \"selected file\";",
+        content,
+    ), "Expected fetch upload failures to include the selected file name in recovery guidance."
+    assert "error instanceof TypeError" not in content, (
+        "Rejected upload requests must not depend on a browser-realm-specific error type."
+    )
+
+    print("✅ Unreadable chat upload guidance passed")
+
+
 def test_config_version_is_bumped_for_chat_clipboard_upload_support():
     """Verify config version was bumped for the clipboard paste upload feature."""
     print("🔍 Testing config version bump...")
 
-    config_content = read_file(CONFIG_FILE)
-    assert_app_version_at_least("0.241.056")
+    assert_app_version_at_least("0.261.032")
 
     print("✅ Config version bump passed")
 
@@ -130,6 +160,7 @@ def test_config_version_is_bumped_for_chat_clipboard_upload_support():
         test_chat_clipboard_paste_reuses_shared_upload_helper,
         test_chat_clipboard_paste_handler_normalizes_missing_filenames,
         test_chat_drag_and_drop_upload_binding,
+        test_chat_upload_reports_unreadable_files_with_recovery_guidance,
         test_config_version_is_bumped_for_chat_clipboard_upload_support,
     ]
 
diff --git a/functional_tests/test_chat_retry_edit_model_endpoint_replay.py b/functional_tests/test_chat_retry_edit_model_endpoint_replay.py
new file mode 100644
index 000000000..5b3a66a9a
--- /dev/null
+++ b/functional_tests/test_chat_retry_edit_model_endpoint_replay.py
@@ -0,0 +1,134 @@
+# test_chat_retry_edit_model_endpoint_replay.py
+#!/usr/bin/env python3
+"""
+Functional test for retry and edit model endpoint replay.
+Version: 0.261.033
+Implemented in: 0.261.033
+
+This test ensures retry and edit requests preserve the model endpoint identity
+used by the original streamed response instead of falling back to the default
+Azure OpenAI resource with only a model or display name.
+"""
+
+import ast
+import os
+
+
+ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+CONVERSATION_ROUTE_FILE = os.path.join(
+    ROOT_DIR,
+    'application',
+    'single_app',
+    'route_backend_conversations.py',
+)
+RETRY_JS_FILE = os.path.join(
+    ROOT_DIR,
+    'application',
+    'single_app',
+    'static',
+    'js',
+    'chat',
+    'chat-retry.js',
+)
+
+
+def read_file_text(file_path):
+    with open(file_path, 'r', encoding='utf-8') as file_handle:
+        return file_handle.read()
+
+
+def load_replayed_model_context_builder():
+    route_source = read_file_text(CONVERSATION_ROUTE_FILE)
+    route_tree = ast.parse(route_source, filename=CONVERSATION_ROUTE_FILE)
+    helper_node = next(
+        node
+        for node in route_tree.body
+        if isinstance(node, ast.FunctionDef)
+        and node.name == '_build_replayed_model_context'
+    )
+    helper_module = ast.Module(body=[helper_node], type_ignores=[])
+    helper_namespace = {}
+    exec(compile(helper_module, CONVERSATION_ROUTE_FILE, 'exec'), helper_namespace)
+    return helper_namespace['_build_replayed_model_context']
+
+
+def build_original_metadata():
+    return {
+        'model_selection': {
+            'frontend_requested_model': 'gpt-5.6-luna',
+            'selected_model': 'resolved-azure-deployment',
+            'model_id': 'model-luna',
+            'model_endpoint_id': 'endpoint-luna',
+            'model_provider': 'aoai',
+            'model_icon': {'kind': 'bootstrap', 'value': 'bi-moon'},
+        },
+    }
+
+
+def test_edit_replays_original_model_endpoint_identity():
+    builder = load_replayed_model_context_builder()
+
+    replayed_context = builder(build_original_metadata())
+
+    assert replayed_context == {
+        'model_deployment': 'gpt-5.6-luna',
+        'model_id': 'model-luna',
+        'model_endpoint_id': 'endpoint-luna',
+        'model_provider': 'aoai',
+        'model_icon': {'kind': 'bootstrap', 'value': 'bi-moon'},
+    }
+
+
+def test_retry_selection_preserves_or_replaces_endpoint_identity():
+    builder = load_replayed_model_context_builder()
+    original_metadata = build_original_metadata()
+
+    same_model_context = builder(original_metadata, {'model': 'gpt-5.6-luna'})
+    assert same_model_context['model_endpoint_id'] == 'endpoint-luna'
+    assert same_model_context['model_id'] == 'model-luna'
+
+    changed_model_context = builder(original_metadata, {'model': 'legacy-deployment'})
+    assert changed_model_context['model_deployment'] == 'legacy-deployment'
+    assert changed_model_context['model_endpoint_id'] is None
+    assert changed_model_context['model_id'] is None
+    assert changed_model_context['model_provider'] is None
+
+    explicit_context = builder(original_metadata, {
+        'model': 'new-request-model',
+        'model_id': 'new-model',
+        'model_endpoint_id': 'new-endpoint',
+        'model_provider': 'openai',
+    })
+    assert explicit_context['model_deployment'] == 'new-request-model'
+    assert explicit_context['model_id'] == 'new-model'
+    assert explicit_context['model_endpoint_id'] == 'new-endpoint'
+    assert explicit_context['model_provider'] == 'openai'
+
+
+def test_retry_frontend_sends_complete_model_identity():
+    retry_source = read_file_text(RETRY_JS_FILE)
+
+    assert 'selectedOption?.dataset?.requestModel' in retry_source
+    assert 'requestBody.model_id = selectedOption?.dataset?.modelId || null;' in retry_source
+    assert 'requestBody.model_endpoint_id = selectedOption?.dataset?.endpointId || null;' in retry_source
+    assert 'requestBody.model_provider = selectedOption?.dataset?.provider || null;' in retry_source
+    assert "requestBody.model_icon = JSON.parse(selectedOption?.dataset?.modelIcon || '{}');" in retry_source
+
+
+if __name__ == '__main__':
+    tests = [
+        test_edit_replays_original_model_endpoint_identity,
+        test_retry_selection_preserves_or_replaces_endpoint_identity,
+        test_retry_frontend_sends_complete_model_identity,
+    ]
+    results = []
+    for test in tests:
+        try:
+            test()
+            print(f'{test.__name__}: passed')
+            results.append(True)
+        except Exception as exc:
+            print(f'{test.__name__}: failed: {exc}')
+            results.append(False)
+
+    raise SystemExit(0 if all(results) else 1)
\ No newline at end of file
diff --git a/ui_tests/test_chat_clipboard_paste_upload_workflow.py b/ui_tests/test_chat_clipboard_paste_upload_workflow.py
index 758fcacbf..d1e15eb08 100644
--- a/ui_tests/test_chat_clipboard_paste_upload_workflow.py
+++ b/ui_tests/test_chat_clipboard_paste_upload_workflow.py
@@ -1,13 +1,14 @@
 # test_chat_clipboard_paste_upload_workflow.py
 """
 UI test for chat clipboard paste upload support.
-Version: 0.241.056
-Implemented in: 0.241.056
+Version: 0.261.032
+Implemented in: 0.241.056; expanded in: 0.261.032
 
 This test ensures that pasting a clipboard image into the main chat input
 routes the file through the existing upload flow, auto-creates a conversation,
 normalizes an empty clipboard filename, preserves later text paste events, and
-uploads dropped files through the same chat flow.
+uploads dropped files through the same chat flow. It also verifies that an
+unreadable dropped file produces actionable guidance without an upload request.
 """
 
 import json
@@ -97,6 +98,7 @@ def handle_get_conversations(route):
         (() => {
             const originalFetch = window.fetch.bind(window);
             window.__uploadCapture = [];
+            window.__rejectNextUpload = false;
 
             window.fetch = async (input, init = {}) => {
                 const requestUrl = typeof input === 'string' ? input : (input && input.url) || '';
@@ -108,6 +110,10 @@ def handle_get_conversations(route):
                         fileName: file ? String(file.name || '') : '',
                         fileType: file ? String(file.type || '') : '',
                     });
+                    if (window.__rejectNextUpload) {
+                        window.__rejectNextUpload = false;
+                        throw new DOMException('Failed to fetch', 'NetworkError');
+                    }
                 }
 
                 return originalFetch(input, init);
@@ -255,6 +261,72 @@ def handle_get_conversations(route):
         assert upload_capture[1]["fileName"] == "drop-notes.txt"
         assert upload_capture[1]["fileType"] == "text/plain"
 
+        page.locator("#user-input").evaluate(
+            """
+            (element) => {
+                const unreadableFile = new File(
+                    ['locked document'],
+                    'open-in-onedrive.docx',
+                    { type: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document' }
+                );
+                Object.defineProperty(unreadableFile, 'slice', {
+                    value: () => ({
+                        arrayBuffer: () => Promise.reject(new DOMException('The requested file could not be read')),
+                    }),
+                });
+                const dataTransfer = new DataTransfer();
+                dataTransfer.items.add(unreadableFile);
+                const dropEvent = new DragEvent('drop', {
+                    bubbles: true,
+                    cancelable: true,
+                    dataTransfer,
+                });
+
+                element.dispatchEvent(dropEvent);
+            }
+            """
+        )
+
+        unreadable_file_toast = page.locator("#toast-container .toast").last
+        expect(unreadable_file_toast).to_contain_text(
+            'The browser could not read "open-in-onedrive.docx".'
+        )
+        expect(unreadable_file_toast).to_contain_text(
+            "Close the file in other apps then try again."
+        )
+        assert page.evaluate("() => window.__uploadCapture.length") == 2
+
+        page.evaluate("() => { window.__rejectNextUpload = true; }")
+        page.locator("#user-input").evaluate(
+            """
+            (element) => {
+                const droppedFile = new File(
+                    ['cloud document'],
+                    'open-cloud-document.docx',
+                    { type: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document' }
+                );
+                const dataTransfer = new DataTransfer();
+                dataTransfer.items.add(droppedFile);
+                const dropEvent = new DragEvent('drop', {
+                    bubbles: true,
+                    cancelable: true,
+                    dataTransfer,
+                });
+
+                element.dispatchEvent(dropEvent);
+            }
+            """
+        )
+
+        rejected_upload_toast = page.locator("#toast-container .toast").last
+        expect(rejected_upload_toast).to_contain_text(
+            'The browser could not upload "open-cloud-document.docx".'
+        )
+        expect(rejected_upload_toast).to_contain_text(
+            "The file may be open in another app, unavailable from cloud storage, or the network connection may have been interrupted."
+        )
+        expect(rejected_upload_toast).not_to_contain_text("Failed to fetch")
+
         expect(page.locator("#current-conversation-title")).to_have_text("Clipboard Upload Conversation")
     finally:
         context.close()
diff --git a/ui_tests/test_workspace_active_hero_shortcuts.py b/ui_tests/test_workspace_active_hero_shortcuts.py
index 89e07d7a8..17c845a09 100644
--- a/ui_tests/test_workspace_active_hero_shortcuts.py
+++ b/ui_tests/test_workspace_active_hero_shortcuts.py
@@ -1,7 +1,7 @@
 # test_workspace_active_hero_shortcuts.py
 """
 UI test for active workspace hero shortcuts.
-Version: 0.241.152
+Version: 0.261.003.01
 Implemented in: 0.241.125
 
 This test ensures the group and public workspace pages render the active hero
@@ -9,6 +9,8 @@
 selected workspace. Updated in 0.241.151 to validate public workspace dropdown
 search and implicit public User role display. Updated in 0.241.152 to validate
 public workspace search remains visible for smaller public workspace lists.
+Updated in 0.261.003.01 to validate the public workspace dropdown dark-theme
+colors match the group workspace selector.
 """
 
 import base64
@@ -431,6 +433,40 @@ def test_public_workspace_active_hero_and_manage_link(playwright):
         assert _selector_row_contains_public_controls(page), (
             "Expected the public selector, role summary, manage button, and My Workspaces button in one row."
         )
+        page.evaluate("document.documentElement.setAttribute('data-bs-theme', 'dark')")
+        selector_row_class = page.locator("#public-selector-row").get_attribute("class") or ""
+        assert "workspace-toolbar-row" in selector_row_class
+        page.locator("#public-dropdown-button").click()
+        first_dropdown_item = page.locator("#public-dropdown-items .dropdown-item").first()
+        first_dropdown_item.evaluate("el => el.classList.remove('active')")
+        first_dropdown_item.hover()
+        hover_background = first_dropdown_item.evaluate("el => getComputedStyle(el).backgroundColor")
+        page.mouse.move(0, 0)
+        dropdown_colors = page.locator("#public-dropdown-menu").evaluate(
+            """
+            menu => {
+                const searchContainer = menu.querySelector('.public-search-container');
+                const firstItem = menu.querySelector('.dropdown-item');
+                firstItem.classList.add('active');
+
+                return {
+                    menuBackground: getComputedStyle(menu).backgroundColor,
+                    menuBorderColor: getComputedStyle(menu).borderColor,
+                    searchBackground: getComputedStyle(searchContainer).backgroundColor,
+                    activeBackground: getComputedStyle(firstItem).backgroundColor,
+                    activeColor: getComputedStyle(firstItem).color,
+                };
+            }
+            """
+        )
+        assert dropdown_colors == {
+            "menuBackground": "rgb(52, 58, 64)",
+            "menuBorderColor": "rgb(73, 80, 87)",
+            "searchBackground": "rgb(52, 58, 64)",
+            "activeBackground": "rgb(13, 110, 253)",
+            "activeColor": "rgb(255, 255, 255)",
+        }
+        assert hover_background == "rgb(73, 80, 87)"
         expect(page.locator("#btn-change-public")).to_have_count(0)
         assert _is_before(page, "#active-public-hero", "#public-dropdown"), (
             "Expected the active public hero to render above the public workspace selector."