mixing with winforms

We have a mixed application - it is using your UIStudio (WinForms) for a tabbed MDI interface with toolwindows and such, as well as using the SyntaxEditor. We also have one third party grid control that is WinForms. We are building all new custom controls using WPF and hosting them inside WPF Element Host (WF interop) controls.

I really like your other controls and would like to use the WPF ribbon in our UI as well, but we've had lots of problems where we've needed to be very careful not to 'overlap' WF and WPF controls due to the fact that WinForms controls don't participate in the WPF z-order. (you can see my blog about this if you're interested - it's at http://kleahy-technical.blogspot.com).

Anyway, my question is basically whether you think we could effectively use the WPF ribbon in place of our current toolbar infrastructure (newly rebuild to use your UIStudio controls) alongside non-WPF content (in particular, your tab controls).

The structure would be:

• main application: WF
• ribbon hosted in Element Host on WF mainform.
• dock manager on WF mainform from UIStudio
• tabs are WF user controls, some toolwindows are WF, some are WPF hosted in element hosts.
• some of the WF user controls have dock manager on them, and those dock managers have some toolwindows that are WPF hosted in element hosts as well

It's a big mess of interop, i know, but it seems to be working so far (without a ribbon). I'm just trying to understand whether the ribbon will work, as it my potentially 'overlap' some of the winforms controls when it does it's dropdown items. Are those rendered using 'popup windows', or are they just highest in the z-order for the WPF drawing space?

I suspect this will work, because I suspect they must be some sort of popup window (since they also seem to work outside the bounds of the application window), but I'm not sure.