Hi @HansDampf,
With the latest version of GUI Guider, the Widgets panel on the left side now shows the "placed" widgets on each screen, rather than displaying the widget list.
Now, the widget list can be opened from the "widget" icon on the top left area below UI Editor:

Click on it, then click the "Expand" button and you will see all of the new widget list:

BR,
Edwin.