I'm using a tab control on a card.
The tab control has 4 tabs and I'm using the control to show/hide one of 4 groups of controls.
So far, so good, BUT (again

There appears to be no 'Opaque' property for a tab button - so I can't see how to make it transparent.
Also, if I go to 'Colors and Patterns' and select/change the Tab's Fill color - nothing happens EXCEPT for a thin line of the selected colour appearing at the top right border of the recalcitrant Tab button !
The 'Text' color works...
But that seems to be about it... I can't change the highlighted text, border color, bevel or shadow colours. Well, I can change them in the Property Inspector for the Tab button in the IDE byt little (if anything) happens on the card.
To be frank, at this stage I'd be perfectly happy with just a transparent Tab button (so that it 'picks up' the cards background colour...
Sorry, I'm lost... What am I missing please ? Maybe someone can give me a boot in the right direction please ?
TIA
Regards.