How do you "pin" a flash error message in the CP? It's possible to generate a "flash" error message at the top of the control panel like this:

craft()-&gt;userSession-&gt;setError('Your custom plugin error message.');


The message appears at the top of the control panel when the page loads, but then fades away after a few seconds. Is there any way to "pin" the message to the top of the page, so it stays indefinitely?
I have not tried but you could probably use the CP Custom JavaScript plugin to force display of .notification.error as the flash only sets display: none; and does not remove the element.