Application window top margin changes for some mouseover events
In Thunderbird 31.0 the top margin of the application changes, apparently with some mouseover events.
I have the app maximized, and if I mouse over the menu bar and a menu drops down, or if I mouse over a message title in a folder where the title is longer than the column allows (causing a tooltip-style popup of the full message title), the top margin gets a few pixels shorter, causing the whole wondow to jump up slightly.
I don't think it's a theme issue, since I've tried a few alternative themes.
Wšykne wótegrona (1)
Addendum: this is on Windows 7 Pro.
The effect is only noticeable when the application window is maximized. With the window set so it is not full screen, I cannot see any apparent changes to the border of the application (although the margin space could be transparent so the effect cannot be seen).