I'm not sure that I understand how the Windows theme is relevant.
The issue is that the PixInsight window is painted all white - the menus, the icons, everything. Outside of PixInsight, everything is normal. In the one case where I saw this, the menus and such were still selectable, but just invisible (white). If I clicked the left mouse button and moved over an image, I would see the magnified square area moving around with the mouse.
Like I said above, I've only seen this once. I exited and restarted PixInsight and it was fine.
I'll also add that PixInsight depends on the QT5 graphics library. This library is known to have issues with some Windows video cards and drivers. I am using PixInsight on 3 different machines, and they all have some stability issues since PixInsight 1.8.6 came out (prior to that, I had never seen a PixInsight crash in many years of use). My desktop is using a Core i7 processor and using the integrated graphics. I also have a Surface Book and Surface Pro (2017). The two Surface devices also use Intel graphics, but the Surface Book also has Nvidia discrete graphics when connected to the keyboard base. The Intel graphics in particular, are known to have issues with the QT5 libraries. Supposedly, the Nvidia graphics should be stable, but I do not see a difference in PixInsight stability when using the Surface Book and configuring it to run on the Nvidia graphics.
Some troubleshooting steps that you can try involve starting PixInsight from the command line, with some options to control the QT5 libraries. I would suggest the following two commands to try and see if it helps:
pixinsight --opengl:raster
pixinsight --opengl:ES
See this post for a description of these command lines:
https://pixinsight.com/forum/index.php?topic=13197.0I hope that this helps,
-Wade