This might be the solution --- at least the programs I use often in black background unreadable drop-down menus :) You had to install and configure gtk-theme-config (1.2.1-0ubuntu1) (eg. https://imgur.com/XCnzSJr)
Unfortunately, I can not find the root cause, but it is sure that mesa and nvidia update came in at once, after which it happened. -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to mesa in Ubuntu. https://bugs.launchpad.net/bugs/1746771 Title: black background drop-down menu To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/1746771/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp