Clear openfile before unwinding the history, not after

__tests__/history.spec.ts

@@ -152,6 +152,34 @@ describe('openWithHistory', () => {
 		expect(removeSpy).toHaveBeenCalledWith('popstate', expect.any(Function))
 	})
 
+	it('drops the openfile flag before the jump, not after it', () => {
+		const router = setRouter()
+		const file = makeFile({ id: 1 })
+		openWithHistory([file], file, view, folder)
+		router.query.openfile = 'true'
+
+		const order: string[] = []
+		vi.mocked(router.goToRoute).mockImplementation(() => {
+			order.push('route')
+		})
+		goSpy.mockImplementation(() => {
+			order.push('go')
+		})
+
+		openOptions().onClose()
+
+		// history.go() lands on a later task. Until it does the URL still says
+		// openfile=true, and the Files list opens the file again if anything
+		// makes it re-read the route in that window.
+		expect(order).toEqual(['route', 'go'])
+		expect(router.goToRoute).toHaveBeenCalledWith(
+			'filelist',
+			router.params,
+			expect.not.objectContaining({ openfile: 'true' }),
+			true,
+		)
+	})
+
 	it('drops the openfile flag in place when closing a refresh-opened viewer', () => {
 		const router = setRouter({ openfile: 'true', dir: '/photos' })
 		const file = makeFile({ id: 1 })

lib/utils/history.ts

@@ -163,19 +163,28 @@ function closeHistory(): void {
 		return
 	}
 
+	const query = { ...router.query }
+	delete query.openfile
+	delete query.editing
+
 	const offset = currentOffset()
 	if (offset > 0) {
+		// Drop the flag on the entry being left before jumping. history.go() is
+		// asynchronous, and until it lands the URL still says openfile=true:
+		// anything that makes the Files list re-read the route in that window
+		// runs the default action again and opens a second viewer over the one
+		// that is closing.
+		router.goToRoute(routeName(router), router.params, query, true)
+
 		// Jump back past every entry the viewer added, in one step, so the back
 		// button returns to the opening page instead of a previously shown file.
 		window.history.go(-offset)
 		return
 	}
 
-	// Opened from an openfile URL with no pre-viewer entry to return to (refresh):
-	// just drop the openfile flag on the current entry.
-	const query = { ...router.query }
-	delete query.openfile
-	delete query.editing
+	// Opened from an openfile URL with no pre-viewer entry to return to
+	// (refresh): the flag comes off the current entry and there is nothing to
+	// unwind.
 	router.goToRoute(routeName(router), router.params, query, true)
 }