QColorDialog::open() freezes the app the *second* time it is used on Mac

To reproduce the bug on Mac OS X:

• Build and run the attached 'textedit' program under Qt 4.6.1

• Select some of the text in the text edit

• Click the Color toolbar button and choose a color

• Select some more text in the text edit

• Click the Color toolbar button and choose a color — the application is now frozen

If you do the same thing with Qt 4.6.0 the freeze happens the first time you choose a color. On Windows XP & Linux everything works fine.