Troubleshooting UI display issues with new user profiles in Thunderbird on Windows 10 - aecreations/clippings-tb GitHub Wiki

System info:

• iMac (Retina 4K, 21.5-inch, 2019)
• Intel Core i7-8700
• Graphics: Radeon Pro 560X 4 GB

Running Windows 10 in a Parallels VM on macOS Catalina 10.15.7.

Thunderbird doesn't display properly with the default UI (no window title bar, no menu bar) - the main window suddenly disappears from the screen. Clicking on the task bar button for Thunderbird may make it reappear briefly, but it vanishes again when hovering the mouse anywhere within the window. Another symptom: it isn't possible to resize the window.

I suspect a compatibility issue with the graphics card on this iMac.

Reproducible on Thunderbird versions 60, 68 and 78. Turning off hardware acceleration in Thunderbird options doesn't work.

Solution: Turn on the title bar in the Thunderbird window. In Thunderbird versions 68 and 78, right-click on the toolbar, select Customize, then tick the checkbox to show the title bar. In Thunderbird 60, quit Thunderbird, then go to the Thunderbird profile folder, open the file "prefs.js" for editing in a text editor, and then change the user pref "mail.tabs.drawInTitleBar" to "false".