Are you using Flymake + Emacs + GHC Inferior Mode? When I have an Flymake Error raised with red background color in the editor - I can move the mouse over and get an yellow tooltip explaining the error. Unfortunatelly the tooltip disapperas approx. 10 seconds later.
How can I prevent this? My error messages are long and I need time to read :-)
Unless you are really attached to overlays, I find it much more convenient to have the error messages displayed in the echo area. To try out if you like this behavior, you can easily toggle it with
M-x tooltip-mode. If you are the keyboard centric type, also see the discussions on EmacsWiki on how to display FlyMake errors without having to mouseover them:http://www.emacswiki.org/emacs/FlyMake