The "show tooltips" functionality suffered some sort of a regression it seems. It's rather hard to reproduce, but they now sometimes pop up when you're already hovering over another icon. This is in addition to them often getting "stuck" on screen, as previous versions did. They disappear after a while, but it's annoying nonetheless. Reproducible: Sometimes Steps to Reproduce: 1. Move mouse over the panel towards the application launcher 2. open the application launcher Actual Results: Sometimes, the tooltip of the launcher near the application launcher will pop up and block the view. This also sometimes happens when the mouse cursor leaves the panel. Expected Results: Tooltips should appear only if the mouse is over a launcher. They should disappear as soon as the mouse cursor leaves the component. I feel like the main problem here is the detection of the cursor leaving the component - you have to move the cursor back to the panel and out again so that it notices the cursor left the panel.
Can't reproduce, might be a random Qt version problem on your specific system or similar. Please reopen if it keeps happening after future updates.
It's rather hard to reliably reproduce. I've attempted to screencap it: https://dl.dropboxusercontent.com/u/19330332/tooltip_bug.ogv https://dl.dropboxusercontent.com/u/19330332/tooltip_bug2.ogv So basically, the tooltip appears even though the mouse cursor has left the panel, and stays even though the mouse cursor is neither on the panel, nor the tooltip itself. Its rather jarring.
See Bug 353592
*** This bug has been marked as a duplicate of bug 353570 ***
Well, actually... bug 353570 is a duplicate of 352026, not vice versa :P