Yes your Acer pair shows the bug. To fix it:
1. download the qwindows.dll.zip file from:
https://github.com/kevinhendricks/Bu...OnMac/releases
2. Unzip it.
3. Navigate to the Sigil program folder and then inside the platforms folder. Delete the existing qwindows.dll file or move it completely out of the Sigil program folder. Renaming it does not work.
4. Copy in the newly downloaded qwindows.dll into that platforms folder. It should be the only thing in the platforms folder.
5. Now restart your computer and once restarted fire up Sigil and run the same test for the bug with your Acer monitor pair.
The bug seen earlier should now be fixed.
This fix will be part of all new Sigil releases until Qt officially fixes it.
The fixed qwindows.dll can fully replace the one you deleted or moved previously so no need to revert after the testing.
Thanks for testing!