[BUG] QuickView v5 - Unexpected Closing of the Associated Windows Explorer when using "X" button

[taylor-p-mason]

I’ve noticed a consistent issue when exiting QuickView (v5) by clicking the window “X” button. In addition to closing QuickView, it also closes the associated Windows Explorer window. This does not appear to be a system crash — only the originating Explorer window is closed, not all other Explorer instances.

This does not happen if I close the quickview image window using the right click menu > exit, or the ESC or the Mbutton (mouse wheel button), and the issue never happens on any other applications, it's only with closing quickview using the "X" button.

This unwanted action disrupts the workflow, especially when reviewing multiple images from a folder, since the file browser needs to be reopened each time.

I suspect this is an unintended side effect of how QuickView hooks into Windows Explorer? QuickView’s X button handler maybe incorrectly closing its parent Explorer window, right?

Steps to Reproduce:

Open a Windows Explorer window
Navigate to an image file
Open the image with QuickView
Click the "X" button in the QuickView window

Expected Behavior:

Only the QuickView window should close.

Actual Behavior:

QuickView Closes
The same Windows Explorer window used to launch the image also closes
Other Explorer windows (if open) remain unaffected.

Additional Observations:

Closing QuickView using Esc works correctly (Explorer stays open)
Closing using middle mouse button (MButton) works correctly
Closing via Alt+F4 works correctly
Closing via right-click → Close (taskbar menu) works correctly
The issue occurs consistently only when using the "X" button
This behavior is reproducible 100% of the time

This appears to be specific to the "X" button handler. It may be incorrectly sending a close message (e.g., WM_CLOSE) to the parent Explorer window or mishandling a window handle associated with the launching process.

[justnullname]

Thanks for the feedback! I've tested this on both Windows 10 and Windows 11 but couldn't reproduce the issue on my end. I'll review the code to ensure the close events are being handled correctly. Please let me know if you have any additional details to share.

[taylor-p-mason]

Hi, thank you so much for the acknowledgement of this issue despite you were not able to reproduce the issue. I went ahead and tested QuickView version 5 on two more additional different computers;

1. MSI Summit E14 (Windows 11 Professional 25H2 build 26200.8117)
2. ASUS ProArt Studiobook (Windows 11 Professional 25H2 build 26200.8117)

... and the issue remains, 100% reproducible all the time.

So, the issue isn't limited too just mine, it's happening on other machine systems as well, at least for me on my end. Are you running build 26200.8117 (March 31, 2026 — KB5086672)? What else could it be? I could not find any widely documented discussions, as a known bug specific to KB5086672 (26200.8117) that demonstrates this behavior - meaning not confirmed as a known Microsoft bug (as yet).