how-to block ads
Try using the "refresh" function in your browser -- maybe several times. Try "Shift-reload" (normally the F5 key, also try it with the control key).
Another solution, thanks to Nicole-Diana:
A system message immediately removes the "stuck" IM icon.
You can accomplish this by posting in \dev\null and selecting IM for any replies (above the signature box). Then reply to the post, and as soon as you click the system IM, the "stuck" IM icon should disappear.
And another, courtesy of Mauricio:
If you have a user on ignore and that user sends you an IM, you will get the flashing icon, but when you click on it you won't see anything, and the icon will not go away. The solution for this is to take that user off ignore, delete the IM, and if you so wish, put the user on ignore again.