Sidebar apps saving not intuitive

I've just discovered browsing on the internet that it is possible to save the list of apps opened on the sidebar. I've been missing such feature for over a month. 

I must say the current way of making sure an app is saved is not intuitive at all. I never realized there was a tiny little horizontal bar until I read about it on the internet.

There should be a button to save a given app in the sidebar, so the user can find out this feature, otherwise he/she could end up never discovering it is actually possible to save sidebar apps.