Strange overlay at right side on Windows 10

I was testing the installer on Windows 10 and while that worked fine, I noticed something odd when running Briar itself. For some reason there's a narrow white overlay on the right hand side of the app. It sits below the expiry banner but above all other content. Makes it impossible to see the send button, the overflow menu and part of the text.

It does not happen on Windows 11.

Any idea what this could be? Could have something to do with our drawer?