Comment 5 for bug 950556

The fix in revision 11377 apparently triggers a regression with current GTK2/Quartz 2.24.13 [1]:
1) The first time the preferences dialog is opened in the current session, it automatically reopens when closed. Doesn't happen after closing it a second time.
2) Detached dockable dialogs cause a constant CPU load (12-20%) while open, the CPU load goes back to normal when minimizing the dialog, or when attaching it to the main dock in the document window.

The regression seems limited to GTK2 builds with the Quartz backend: neither GTK2/X11 (2.24.13, no patches) nor the experimental GTK3 builds (GTK+/Quartz 3.6.2, GDL 3.6.2) are affected AFAICT.

Testing with available archived Quartz builds:
- not reproduced with r11376
- reproduced with r11378 and later revisions
- not reproduced with experimental GTK3 builds

Testing with current trunk (r11895):
(Partially) reverting the changes from r11377 (see attached diff) restores the old behavior wrt to the preferences dialog not properly closing and wrt to CPU usage for Quartz-based GTK2 builds (if GDK_WINDOWING_QUARTZ is defined) - please review: I can't tell what unintended side-effects the changes might introduce.

[1] possibly fueled by recent changes in GTK2:
- not reproduced with GTK+/Quartz 2.24.10 (+patches from git 2.24 branch up to da324fa2) on 32bit Mac OS X 10.5
- reproduced with GTK+/Quartz 2.24.13 (+patches from git 2.24 branch up to 35a9322e) on 64bit OS X 10.7.4