Taskbar: Auto-hide stops working

Problem: I customized my taskbar to auto-hide and always be on top. Sometimes
it doesn't auto-hide and that causes the taskbar to just stay on top of
whatever I'm trying to work with.

I have had this problem for years with XP and until recently have been able
to fix it by changing settings, applying, putting them back to what I want,
applying, and going on. Recently, though, this stopped fixing it.

There was a workaround posted on a newsgroup (outside MS): open Task
Manager, kill the explorer process, and then start the explorer.exe process
again (File -> New Task) .

Question: Is there a real fix for this? It's annoying.