Remember that your pref pane view is taken out of the window it's in when the nib is loaded, and put into another window (the preferences window). In all likelihood the original window was freed, and your outlet is pointing to a freed object.
Try calling [[myView window] display]. That will call the window that your view is currently in.
I take it just calling [myView setNeedsDisplay:YES] doesn't do it for you? And if not, calling -display on your view and then -flushWindow on the window doesn't work? I'd try both of those before calling -display on the window itself... that's a bit of overkill.