Crazy app behavior - WinUI 3 (Blank screen & crashes)

[gautambjain]

I chose WinUI 3 for my app about 3 years back. I recently launched the app. I didn't work on this app full time. So it took 3 years. Here is the link to my app's website: https://www.conceptworld.com/Filezo. Although people were complaining about WinUI 3 in this forum, I trusted it and liked the new modern UI. Plus I didn't experience any major issue during development until now.

Until now, when the customers are complaining. The app's behavior is very weird as the issues crop up only on certain environment and not every time in the same environment. Due to this I cannot post a repro. Also I cannot see it myself on my system. I have connected to my customer's computer remotely and seen the issues. Not one customer but quite a few.

Here is the summary:

1. The app window appears blank (randomly, not every time). 100% blank or partially blank. Until the app is restarted. Simply restarting the app corrects the issue.
2. The app crashes (every time) when activated via mouse click. I have multiple windows. Clicking on one secondary window shows the main primary app window. But it crashes. However, I support activating the app window via system hotkey. This works. Hotkey works. But clicking on the window crashes the app.
3. I show the Windows File Explorer shell context menu inside the app. On most system it works. But it crashes on some systems, but every time.

All of the above happens on latest Windows 11.

This inconsistent behavior seems to be due to some instability, incompatibility or bad code in WinUI 3.

[gautambjain]

The same blank screen issue exists in PowerToy, WinUI 3 Gallery etc as posted here: microsoft/PowerToys#29340

[michael-hawker]

Seems similar or related to #9024