OS version: Windows 11 PRO Version 21H2 OS build 22000.593
Fresh install on a fresh installation of windows 11. I've setup every needed driver and the system is working fine. When I use certaing features of Lightroom, most often when I try to use the masking tool, the interface is not working properly.
If I select brush tool or every other one in the masking area, nothing happens, no matter what I click and how many times. I noticed that if I make a selection on an instrument nothing happens, if I switch program and come back in LRC the cursor changes indicating the cross for linear gradient for example and LRC actually makes me use it. But the lines that usually show linear or radian gradient dimensions are not shown. In attachment you can find a video to showcase this issue.
This is very frustrating. I noticed that something like this is also happening in Photoshop with certain tools. My guess is some sort of incompatibility with Windows 11.
What I've already tried
Disable GPU acceleration
LRC and PC restart
Total uninstall of all Adobe related tools, run Adobe Creative Cloud Cleaner Tool, reboot, fresh install
I see in your video, that once you started a mask, that the mask panel is not being displayed.
Is your LrC screen maximized? If so, reduce it to normal, and if the mask panel shows up, probably not docked under the histogram, do so. A maximized screen may then behave better, that is the mask panel might not go missing, after that.