Things broken in Insider Preview that will eventually be fixed but they're not a priority:
* Taskbar being fully transparent (fixed for now)
* Taskbar thumbnails not working (fixed)
* Disable Snap quadrants not working
* Disable Recommended section in Windows 11 Start menu not working (the live visual tree of the menu probably changed again; it should be an easy fix in lvt.c once the new visual tree is inspected) (this is a phony report, just checked on it, it seems to work fine)
* When pressing volume keys, no volume flyout is shown, because the old one was probably tossed away and no one linked the new one to the old shell; maybe enabling the old one would still be cool, idk, as usual, it has to be investigated
* WiFi flyout does not work anymore, I think (the patch for it is probably broken, the pattern I was searching for may not be there in the binary anymore - InjectShellExperienceHost is the starting point and the article here:
Functional Windows 10 flyouts in Windows 11)
* Toasts and parts of the new shell seem to display on top of the taskbar, yet another thing they broke
* Win-Tab seems not to work anymore
* Disable rounded corners is broken
As you see, the list is pretty huge, and with each update it will become worse. I hope to fix this at least until the first 11-based LTSC ships. Although, to be honest, I wish there was en easier way, fighting the upstream is a lost cause imo.