Layout buttons misaligned and unusable

When editing a QML file with the Qt Quick designer, the layout buttons are sometime misaligned and become unusable.

Here are the steps to reproduce it very easily:

• Open a QML file into QtCreator
• Switch to the designer
• Select a component
• Click on the Layout tab. At this step every thing is fine.
• Switch back to the editor but don't change anything in the QML file.
• Switch back again to the designer and now the layout buttons are misaligned.

It's possible to get the button aligned correctly by:

• click on the component tab to see its properties.
• Switch back to the editor but don't change anything in the QML file.
• Switch back again to the designer and now the layout buttons are aligned correctly.

I attached a video showing how to reproduce it.