MacOSX/Cocoa: non-native QFileDialog steals focus away from file name I am typing after one or two characters are typed

Under Qt 4.6.1/Cocoa for MacOS/X (Snow Leopard), the non-native file dialog steals my focus away when I'm trying to enter a file name into the dialog's QLineEdit.

To reproduce:

1) Compile the attached example program
2) Run the program
3) Choose "Open File" from the menu (or press Command+O)
4) When the file dialog appears, don't use the mouse for anything, just start typing in a file name
5) Note that after the first or second character, you can't type anymore... the line edit has lost the focus, and pressing a key only results in a system beep.

In case you have any problems reproducing this bug, I've recorded a screen movie of me reproducing it also. You can view that movie here:

http://www.screentoaster.com/watch/stUk9XRkFIR19aR1ldXFtaV1BQ/qt_non_native_file_descriptor_bug