You don't say what version of OpenStack you are running, but I thought I would just mention that in Queens at least, the Identity tab in Horizon is essential for users if they belong to more than ~20 Projects because the Project drop-down in the GUI won't display them all and the user needs the Identity tab to select any projects not shown in the drop-down.

This may not apply to you, but I think it's worth being aware of.

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MC