This used to drive me nuts – sometimes I need to know what that window says, such as the status of a program (online or offline), or my IP address, etc. No matter how much I fiddled with the cursor or repeated the attempt to see it, it wouldn’t work until some random time later on. Then I found the fix for it.
And the solution makes about as much sense as the problem. Both seem to be random. Anyway, if this happens to you, here’s what to do: