Opening any File Dialog breaks the viewer in FullScreen

Environment

Second Life Release 7.2.0.16729091892 (64bit)

Description

If you have the viewer in exclusive FullScreen mode and attempt to open any file dialog such as uploading something or saving something. If you attempt to click back into the viewer without first closing the file dialog (so don't click okay or cancel, or X out), the viewer completely breaks and can no longer be interacted with and forcefully minimises itself when you try, and also now the file dialog is missing. The only way to fix the viewer is to forcefully close it with Task manager, Alt+F4 doesn't work and closing the window from the task bar doesn't work either.

This only occurs if you run the viewer from the exe directly (or a shortcut to it), but doesn't occur if it is the child process of another process. Such as running it with or without the Visual Studio debugger makes the issue not occur.

I can only confirm this issue occurs on Windows, in both Windows 10 and Windows 11, I don't know about MacOS or Linux.

Unfortunately I cannot record the issue occurring since between every minimise and maximise, the recordings screen goes black for numerous seconds. But it should be easily reproducible following the below steps.

Reproduction steps

1. Launch the viewer directly and not through Visual Studio or as a child process of any other application
2. Enter FullScreen on the viewer if not already (Debug settings, otherwise if using Firestorm it is simply under graphics in preferences)
3. Cause any File Dialog window to appear such as uploading an image, or saving a texture in your inventory
4. Instead of closing the file dialog, click back into the Viewer
5. You will now be unable to use the viewer, and trying to interact with it will minimise it.

Start by reproducing the Windows-only failure using the listed fullscreen and file-dialog steps, then inspect the viewer's fullscreen and file-dialog handling. Done means the viewer remains interactive when focus returns before the dialog is closed, without minimising or requiring forceful termination.