Bug 106936

Please make all CVS diff/history pop-ups appear on mouseover, as opposed to mouseclick.

Specifically, I refer to the following pop-ups:
1. tags list in Search History
2. commit comments in Search History
3. in-editor diff (the one you get, when clicking a blue stripe in the editor)

The way it works now in Search History requires clicking a column in the line with the interesting revision. The problem
is this has additional effect of changing the selected revision and re-displaying the diff content for it (so you lose
the scroll position, etc.). Additionally, in my opinion mouseover behavior doesn't have any disadvantages over
mouseclick, but is more discoverable and requires less effort (right now it's not only the click to show the pop-up, but
also another click to hide it, and you have to know, where to click).

The way I suggest to do it is waiting for a configurable amount of time (300ms by default) after the mouse has been
positioned over the relevant element, then displaying the pop-up. Similarly, when the mouse is moved out of it, wait for
a configurable amount of time (500ms by default) and, if the mouse is still out, close the pop-up.