Tab Leader not working as desired

Hi,
I have inserted certain tabs in my text in the text area. I want those tabs to be leaded by some specific characters. What I know I can use Tab Leaders for that. Am I correct? Or is Tab leaders for some other use.

When I am trying to use the TAB leaders, I can not see the tab leader inserted where ever I have tabs inserted. Why is it so?

Regards
Rajesh Chadha