Changing MultiScaleImage Source Bug

When I change the source on my multiscale image it does what I expect and loads the new tiles, however it seems to mess up the controllers... Specifically, I lose all control with the mouse except for single clicking to zoom in. What is really weird is that if I take focus away from the browser (Firefox) and then bring it back up it starts working again.

I'm doing this on a Mac, so I'm guessing that it has something to do with the hacks required to get mouse zooming working... But what would that have to do with changing the source?

Should I be doing something else to update the source on a multiscale image?

thanks,
Pat