Customized toolbars in Theme Editor
In order to define a customized toolbar, you should:
Rigth click on the Mainmenu area and select customize (then you can add a new toolbar)
This creates a floating toolbar (you can select whether you want it at the top, bottom, left or rigth)
You can add buttons to the menu using drag&drop:
This opens the Customize dialog. In the Commands tab, you can select a command to drag and drop.
Then you can place it where you want inside the workspace.