About the Save, it is very simple and efficient. I copy here what I put in my updated Step by Step guide 2.0.
Under File, select Save or Save As to save your panel. A file with .panel as extension will be created.
When you use Save, you are saving your work in the current panel file. When you use Save versioned, you are storing the whole panel in a new file as DSI Pro2_1_0_2017-03-20_16-02.panel while staying in the current panel file. The filename of the “Saved versioned” file is automatically created and includes the current version and date/time. The Version MINOR panel attribute is incremented automatically at each save versioned.
About SetVisible, I don’t remember but I think I just avoided touching that at panel load…