Hi Vikram,
Mr. Samuli's code will not work if you place it in your component as selection screen belongs to other used component.
Only possible option to remove ':' from selection screen is to copy the component WDR_SELECT_OPTIONS and write the above suggested code in view SELECT_OPTIONS.
Now, use this ZWDR_SELECT_OPTIONS in your component for bulding selection screen.
Or, you can also enhance the view SELECTION_SCREEN of component WDR_SELECT_OPTIONS and add the code to meet your requirement.
But, it is not suggested as it applies to many components.
Hope this helps you.
Regards,
Rama