[rap-dev] Bugfixes change Shell sematics

[Ralf Sternberg <rsternberg@xxxxxxxxxxxxxx>]

Hi all,

our Shell implementation had a couple of annoying bugs that we wanted to 
fix in this release. Namely, the z-order of shells was sometimes a bit 
unpredictable, dialog shells dropped below their parents, shells that 
should be blocked by a modal shell became operable after certain click 
sequences (bugs 197274, 203744, 224879).

While working on these bugs, some changes in the semantics of the Shell 
were unavoidable. We decided to commit these changes into RC1 anyway, 
because they ensure a consistent behavior that is now very close to SWT.

The most obvious changes are:

* Dialog shells are now always displayed above their parent shells, as 
they are in all common desktop environments.

* Raising a dialog shell also raises the related top-level shell and 
all it's dialogs, as common window managers do.

* Closing a shell automatically closes all dependent dialog shells. 
However, a ShellListener on a dialog shell can not keep the related 
parent from closing. This exactly matches the behavior in SWT.

Due to the restrictions of the current Window implementation in qooxdoo, 
there are still differences to SWT which we cannot solve in this release:

* Shells with ON_TOP style are not blocked by modal shells (bug 232468).

I hope these changes fix your apps instead of breaking them :)

Best regards,
  Ralf