QuickCUI introduced in AutoCAD 2008

Right click on a toolbar in AutoCAD 2008 and the command QuickCUI will be started. It opens up CUI (Customize User Interface) quicker but you will not see the actual toolbar that you right clicked on until you click on Customizations in ... pane (Customizations in All CUI Files as seen below).
The CUI dialog box is displayed in a collapsed state. Only the Customizations in ... and Command List panes are displayed. The Customizations in ... pane is shown collapsed and the Command List pane is shown expanded. So the QuickCUI command is useful since it opens up quicker than the CUI command.

Customizations in All CUI Files expanded and since I right clicked on the Standard toolbar that one is selected.

To see everything click on the arrow in the circle at the bottom right.

You don't end up on the button you right clicked on but close enough.