Credit for this find goes to Adobe. I was recently working with an extension that created views and ran into a frustrating issue. Even though I was using toolbars, the toolbars would not show up. I dropped that extension for a while and later tried working on another extension. Once again I ran into an issue - this time with the icon attribute. (This creates a little icon to the left of your view title.)

Adobe discovered that there is a bug by where the views you create will cache their rendering chrome. By that I mean the toolbars and icon, not the stuff in the view. The bug bites you when you create a view that does not use these options and then modify it later.

To fix it, simply change the ID value of your view window. There is a bug logged for this already (you can view/vote for it here) but luckily this is easy enough to get around.