These are image-based tabs.

These tabs have additional settings, so selected tab looks like it was brought to the front.
This effect is achieved with the help of additional items with individual styles. So, the tabs has the following structure:

Item1 separator Item2 separator Item3 separator Item4

Where separator is the additional item, that creates bring-to-front effect.
Each separator has 7 states:

                                   

For more info see parameters info.