Hi Andy,

thank you for your thoughts.

The way I load up the ppam is:
Save it to C:/Users/MyName/AppData/Roaming/Microsoft/Addins
Open PowerPoint, go to File, go to Options, go to Addins
Go to Manage at the bottom of the window, choose PowerPoint Addins, then click Go
And in the new window click on "Add new" and select the ppam.

The tab appears, every macro works - except the one to make the tab the active one, while even this macro works when I open the pptm on the same machine.

Do you see any mistake in my way to proceed?

Thank you!
RG