EditMarkerDialog resizes incorrect

To get the dialog:

1. Open WD.
2. Add "Sequence Marker" element to the scene and select it.
3. Click "Add" button on the parameter widget.
   Expected state: the "Create Marker Group" dialog appeared.
4. Select the default marker ("Rest"), click the "Edit" button.
   Expected state: the "Edit Marker" dialog appeared.

You can't resize this dialog by the dragging it by corner, but the dialog has the "Maximize" button.
Remove the "Maximize" button and allow the dialog to be resized on the horizontal direction.