R1:e1b8c9d261cd

Fixing a race condition for hovercards

Summary:
Refs T1048 - Take this setup:

D123 D321

Hover with the mouse over one object, and move to another one before it got loaded. You'll have two hovercards. Of these you can't get rid of one anymore. Not through resizing, not through showing another hovercard. (You may have to try a few times). I think it only happens when #2 loads faster than #1. #2 is displayed, then #1 gets loaded and draws.

Or something like that. You could have a race condition where one…