Hi Pawel,
I am not quite clear on what problem you are having. I think it's that you don't have enough room to place all of your controls on the Front Panel of your VI? I am not sure why you had trouble with the Tab control. I built a quick example of one to see if it works on your machine.
Also, if you are wanting to build an object, then a cluster is the best way to go. If certain members are private, you can make them invisible by right-clicking on them and select Advanced>>Hide Indicator. Let me know if there's something else you're looking for.
J.R. Allen