Tabs and buttons not correctly (re)drawn
Sometimes, when I click on links, all the tabs "disappear". If I switch windows (alt-tab) or hover over the tabs, they are nicely redrawn. Sometimes also the buttons of forms are not drawn until I hover over them. It just happened to me when I clicked the "This happened" drop-down menu.
Wšě wotmołwy (1)
By the way: I already tried disabling all add-ons and plugins.