Mark activities as favorite

In the workflow designer, there is a number of activities that I use often, e.g. Cast, Log, Set Property and some more. 

I'd like to have a special category at the top of the activity toolbox where I can add my favorite activities, so that I always have those at hand. 

If possible, these favorites should be stored in ArcGIS, and not just in a browser session, so I don't have to set them for every browser or VM that I use.