"Advanced task panes", not so easy as they seemed

On my previous post, New interface for Office 2003 add-ins, I commented that I was excited by the prospect of using the exact same UI in PowerPoint 2007 and previous versions. In fact, I have been able to implement this new concept in my upcoming add-in, PowerMerge in just a couple of days. Great for me!

But wait, "the devil is in the details" they say. And I have discovered that it is not as easy as it seemed at first.

My new interface works like a charm if my add-in is the only one using the advanced task panes feature. But, as I said, I plan to implement this UI in all my add-ins. So what happens if PowerPoint, or Word, are running two or more add-ins that use this "ribbon"?

At the top, you can see the nicely formatted "ribbon" that closely resembles the true ribbon of PowerPoint 2007.

At the bottom, there is how this same "ribbon" would look if a second add-in tries to place its own "ribbon". A header is drawn on top of the task pane to let the user select the appropriate "ribbon" to work with. Unfortunately the task pane height is not modified and the top of the "ribbon" is effectively hidden by the header.

The effect is not nice. So, I have to work out a solution. Time to contact Add-in-Express support again.