Comment 1 for bug 865168

sometimes I think you should leave well enough alone, this is one of those cases where the design is being overwrought
If the app being dropped on is open on that WS then the Dash already auto closes

If it's open on another WS or not at all then a simple click on the icon dismisses the Dash & raises the window

What this little changes is doing though is preventing users from doing multiple DnD from an open Dash
The potential loss isn't reflected in any gain from a user vs. design perspective