tab index problem

Hi
I am working on activewidgets, and i need you people's help. Can any body help me. Actually i am having a grid. And in tat grid i am having one textbox and one combo box. I have given the option in combo box to select the data. But when when even i use to press enter key to select the data from combo, the tab index use to go somewhere. I want the the tab index to be the there. Can anybody help me in this matter.
Thanks
Regards,
Vimal Kumar