I was able to set the text color of a selected LinkBar button by "disabledColor" style of LinkBar. Accordingly, I expect to set the background color of the selected button by "backgroundDisabledColor" style, however, it didn't work; and except "backgroundDisabledColor", I didn't see any other style that could possibly achieve this. Please help. Thanks.
Solved this myself by writing a programmatic skin and set it to LinkButton's disabledSkin.