Standard dialogs' buttons' margins are not large enough with CDE style

When using the standard dialogs provided by QMessageBox, like QMessageBox::question, the Ok and Cancel buttons do not have large enough margins to show the top or bottom of the outer black box.

To replicate this, open the Qt 4.7.1 included example standarddialogs. Once opened, click on the QMessageBox::question() option. You can now see that the "Yes", "No", and "Cancel" buttons only have the black border on the left and right. The black border is missing from the top and bottom.