Hi, Martin,
I checked the available properties, and unless I really overlooked something, I don't believe you can hide the tab itself with the native .NET tab control. Maybe one of the third party tab controls allows you to do it.
Something else to think about..let's say you have three possible 'tab pages'. You could create three distinct user controls (same as 'container classes' in VFP), and add them/make them visible/invisible 'on the fly' in the area of your form where you want to display them.
I did that once where the middle of the screen could contain very different content based on some run-time condition, but didn't want to use tab pages. I don't know your situation, so it might not apply, but figured I'd mention it.
Kevin