IE9, Property Panel disappears when using "Page Layouts"

The Property Panel on Elements doesn't show up.

Steps to reproduce:

1. Use Internet Explorer 9
2. Create a page and select a page layout
3. Insert a link or any other element, which shows a property panel when you left-click on it
4. Insert some more content (text and line breaks are ok), so that the editor shows you a vertical scrollbar
5. Save Page
6. Edit Page again, left-click on the element to show the property panel -> should work
7. Scroll to the end of the page, then try again to popup the property panel -> doesn't work anymore