QFileDialog::getExistingDirectory() incorrectly allows to select multiple directories

Steps to reproduce

1. In your program, call QFileDialog::getExistingDirectory() with any valid parameters. Alternatively, you can use e.g. Qt Creator: Press Ctrl+N, choose any project and press the "Browse..." button.
2. When the dialog is shown, select multiple directories.
3. Press the "Select Folder" button

Expected result

Selecting more than one directory should not be allowed. (See http://doc.qt.nokia.com/latest/qfiledialog.html#getExistingDirectory)

Real result

It is possible to select multiple directories. Moreover, if you do this a blank path is returned (the same as if the user pressed Cancel).

Additional information

This only happens on Windows Vista and higher. (The dialog used here is different from older Windows Versions.)
It also happens with the latest Qt version from gitourious (git clone git://gitorious.org/qt/qt.git).

The problem is that qt_win_CID_get_existing_directory() (src/gui/dialogs/qfiledialog_win.cpp:585) calls qt_win_set_IFileDialogOptions() with QFileDialog::ExistingFiles() (note the plural)(line 600). This could trivially be fixed by just changing it to QFileDialog::ExistingFile(). I have already tested it, and it seems to work now.

Here is the output of git diff after applying the fix:

$ git diff

diff --git a/src/gui/dialogs/qfiledialog_win.cpp b/src/gui/dialogs/qfiledialog_win.cpp
index 78803ba..1924c58 100644
--- a/src/gui/dialogs/qfiledialog_win.cpp
+++ b/src/gui/dialogs/qfiledialog_win.cpp
@@ -597,7 +597,7 @@ QString qt_win_CID_get_existing_directory(const QFileDialogArgs &args)
     if (SUCCEEDED(hr)) {
         qt_win_set_IFileDialogOptions(pfd, args.selection,
                                       args.directory, args.caption,
-                                      QStringList(), QFileDialog::ExistingFiles,
+                                      QStringList(), QFileDialog::ExistingFile,
                                       args.options);

         // Set the FOS_PICKFOLDERS flag