If a session is configured to never show tray icons, and this is changed to normal, an entirely transparent icon will be added to the system tray.
show tray icons
The icon should not be transparent.
gh-2: Transparent icon on x64 through not enough Get*LongPtr
That commit fixes it for the enabling case; I believe other people have been seeing it, if you can reproduce it on a modern version, please raise a new bug.
Added new ESC secuences compatible with 4690. #2
This seems to add code to terminal.c which wasn't included in the 412eb3a commit.