The issue is that the background for SVG thumbnails in File Explorer is transparent. Because of this, the Explorer background often blends with the icon content, making it almost impossible to see (as shown in my attached screenshot). Most icon sets use colors that clash with the Windows 11 dark theme, forcing me to switch to light mode just to browse files.
Your shell extension is currently the only one that offers such extensive customization, and I really appreciate that you've already implemented a fix for this in the Preview Handler. It would be great to have a similar background color setting for Thumbnails as well.
P.S. I also noticed a strange vertical line/artifact in the Text Editor within the Preview Pane. I couldn't find a way to remove it; it looks like a UI bug. (See the right side of the code view in the screenshot).
