New registry system variable @AGO is added for hiding Add Apps Icon(only for user’s tabs) and build-in tabs(All tab and Connectors tab).

note:These controlling bits can be combined to produce cumulative effects. for example, @AGO=6 is combination of @AGO=2 and @AGO=4

@AGO=0; //defalt option, show build-in tabs and not show Add Apps Icon in user's tab.
@AGO=1; //show Add Apps icon on user's tab
@AGO=2; //hide Data Connectors tab
@AGO=4; //hide All tab