You can change a number of settings that affect the appearance and behavior of a floating toolbar.
When you are in Customize mode, moving the mouse cursor over a floating toolbar displays a small icon () will appear to the top-right of the toolbar. Clicking this icon displays the following context menu.
If you're not in Customize mode, you can also display this menu by right-clicking an empty part of the toolbar itself (although this may not be that easy, if for example the border has been turned off).
You can float multiple copies of the same toolbar if desired, and Opus will remember the settings for each one individually.