It is possible to hide toolbars from the main window without opening the toolbars dialog. Just click on the downward pointing arrow that appears to the far right of each toolbar as shown below:
Toggle the checkbox to switch the toolbutton's visibility.
Note: If the down arrow is not visible, then undock the toolbar and redock it and it will reappear. After rebooting Delphic Oracle, the arrows will then appear in the proper proportion (without hiding some of the toolbuttons with a double right arrow).