According to this page, this is how you set up the active tab:
However, when at any time you work on one of the tabs content (or even the tab itself) Active Tab suddenly switches to this tab. So basically the last tab you were working on become the default tab.
So much for convenience, especially when you have many tabs where some require the default to be on None, others the first tab, etc. And so you have to be careful each time "did I set the active tab to none for tab xyz?"
Sorry, but this is RIDICULOUS.