Disable Silverlight-Control in WebPart if site locked

Question

Hello,

i have written some webparts with embedded silverlight controls. If the user select "Edit" on a listitem from the page, a modal dialog opens and the whole "parent"-page will be locked and gets darker. Not my silverlight-control, it keeps working an is still a white as i designed it. How can I react on a modal dialog and disable/hide the silverlight-control? The standard SilverlightWebPart works fine: it hides the SL-Control). So which event, property or what ever do i have to check?

Tanks
Ernest