@PeterJones I haven’t heard anything from @chcg or anyone else, but I’ve been fiddling.
I’ve recently determined that 1) this problem is ongoing with all NPP releases through 8.4.6, and 2) it does NOT occur in dark mode. The issue will return as soon as one switches back to “light” mode. (Not a dark mode fan anyway.)
I decided to look into the cause. I started by copying the existing v2.4 code base from Github and comparing it to the latest NPP v8.4.6 source. It appears to me that this problem is related to changes in the handling of WM_ERASEBKGND messages in the NPP DockingDlgInterface class that were added for the handling of dark mode.
I’m going to update some of the include files and attempt to fix this issue. Never worked on a project served from Github. Hopefully when I start making pull requests, I can work with @chcg to help get a new release addressing this issue.