Hello.

I have multiple tabs installed:
Tab1 contains Tab1A, Tab1B and Tab1C.
Tab2 contains Tab2A, Tab2B and Tab2C.
Tab3 contains Tab3A, Tab3B and Tab3C.

I know how to configure the default sub-tabs are as follows:

click Tab1 --> default Tab1_A
click Tab2 --> default Tab2_B
click Tab3 --> default Tab3_C

Thanks and sorry for my bad English