Showing previews after a delay allows the user to move the mouse around
the screen without triggering constant pop-ups.
Make sure we remove the pop-up when the user hits Escape and redisplay
the pop-up if we are updating the section results due to a change in space
allocated for it.
Rename protected variable _hasPreview to _showPreview in order to not have
the naming conflict with a new private variable _havePointer, which we
name in first person.
dcc0f368bd