Comment 7 for bug 1870111

@osomon One way to cause Thunderbird to freeze the system except mouse cursor and TTY can be accessed: Try opening a clean/fresh/purged then reinstalled installation of Thunderbird and set up email like yahoo or google, as the emails sync, click on the hamburger/three short parallel horizontal icon on the left, click Preferences, click Toolbar layout, then disable the title bar. After closing the Toolbar layout window, two orange (Ubuntu default theme) dots are still shown on the dock beside the icon. Clicking the icon causes the issue. Issue also occurs also on the snap package.