Try setting the label width to 0 and replace the tabs with buttons. Your button can be set use "to go to object" and specify an object on the specific tab that you have used the object info palette to name.
Your buttons can then be given conditional formats.
Hey that's pretty cool. The tabs with zero width look like match sticks but you can still navigate the tabs, and I guess you could have the object be hidden a hidden text (text color same as background) that would be the same text as the name of the button
But what formula do you use to call forth conditional formating?
Right click the object in layout mode and select "conditional formatting"
Is there a way to format tabs so that the selected tab displays the label on a different color for easy identification?
Another way is to give empty names to your tabs ( really not empty, but one space, two spaces... and so on )
Now, in Layout Mode,
1) select the first tab and with the text tool, write a coloured label for the first tab and black ones for the other tabs.
2) select the second tab and repeat point 1) but colouring the label of the second tab
3) do the same for all your tabs. ( best visual results writing one text object for ALL the labels, copying it and pasting it on next Tab in the same position, and changing the respective colors )