mouse click highlight

Hi,
i am currently trying to create a macro in microsoft office word 2003 to highlight the current line. The problem is that i have to enter a key combination to use that macro and it doesnt accept the left mouse click. So, i consider writing the macro in the VB editor(6.3) inside microsoft word. Can anyone help me how to code a macro to highlight the line on which the cursor lies? and if i move the cursor with the mouse i want the highlight to be moved to the new line the mouse clicks too.
This feature exists already in other text editors such as UltraEdit.....but i have to use microsoft word.

Thanks, John