Version details: 1.5.1 rc1
Distribution/Version: XP

Open gnumeric.  Before you do anything else, left click between say the 5th and
6th rows.  You should get a little yellow tooltip popup saying something like
"Height: 12.75pts (17 pixels)".  One of two things may happen.  Either this
tooltip just flashes away when you release the mouse button (good) or it sticks
around (bad).  Which one occurs may depend on if you wiggle the mouse slightly
as you click -- I'm not sure.  If you get the good outcome, close gnumeric and
try again; after a few tries I consistently get the bad outcome.  In this case
you are stuck resizing the row, with no way I can find to get unstuck.  And the
tooltip sticks around on top even when you switch to another application.