Designer WYSIWYG interface is not consistent with the actual runtime user interface in some cases

Designer WYSIWYG interface is not consistent with the actual runtime user interface in some cases. Here's an example:

• start with a main window
• drag a dock widget
• drag two combo boxes side by side into the dock widget
• select both combo boxes, hit horizontal layout
• drag a widget (QWidget) below the two combo boxes
• Select the dock widget and hit vertical layout

The dock widget will resize to the minimal size.
You can now resize the dock widget and the top horizontal layout and the bottom widget will resize the same amount. However, this is not the runtime behavior. If you hit the preview, the runtime behavior is keeping the top horizontal layout at the top while resizing the widget at the bottom. The problem can be fixed by changing the sizing policy if the widget to expanding, though.