We encounter an issue when we have a docking window in float mode and when we open a Modal.
Indeed it's still possible in that case to interact with the floating docking window.
I tested with the sample as well, and it's possible to reproduce the problem.
For instance in Docking/MDI - demos and Simple IDE(in-line), we undock the Solution Explorer to put it float, and click on the menu File->Open, the Open dialog is modal so we cannot interact with the parent, but it's possible to move and even dock back the Solution Explorer.
Is it a known issue ? I did not see anything related to this with the latest maintenace release notes.