You need to use Remove/Add methods instead

Best Regards,
Nevron Support Team

I have tried that with no results.

manager.Toolbars.SetIndex(manager.Toolbars["UI Editor"], 0);

Hi Billy,

The order of the toolbars on same row depends of their order in NCommandBarsManager.Toolbars collection.
To set a toolbar to be on the leftmost position it should be at the first place in toolbars collection.

Best Regards,
Nevron Support Team

I have the same problem.
I have added a toolbar to the manager.
Now I want the toolbar to be the leftmost toolbar.
I only have my custom toolbar and the Standard toolbar.
No matter what I have tried, the Standard always is leftmost.