Filename completion in QFileDialog::getOpenFileName() eats first character

Steps to reproduce / test case:

• launch the "Standard Dialogs" from the qtdemo and click on the "QFileDialog::getOpenFileName()" button
  (don't use native dialogs!)
• in the QFileDialog box go to the toplevel directory of a drive, e.g. "d:"
• type into the filename lineedit the first character of an existing file and choose one from the
  listbox with the suggested files
  --> the first character of the file is missing!!!

More information:

This error only appears on the toplevel directory of a drive!