mouseover text should display the name of the current document for opened applications

[Damien]

Currently the mouseover text always displays the name of the application. It would be better to:
- show the application name when the application is closed and pinned to the dock,
- show the name of the opened document (if any) when the application is up and running.

This would allow the user to see which document is opened by just hovering the application icon without having to bringing it forward. It's also a subtle marker of which application is currently opened and in use.

[Nishant George Agrwal (niagr)]

what would you expect to see if there are multiple instances of the application open (multiple documents) ?

[Damien (youpla-b)]

Multiple lines? perhaps with the last on top in bold? This need to be rethought as how to present multiples instances in the dock. Also see bug 1083359 .