web app - image button - removing dotted outline when selected

Hi,

     I have a menu that's created with a combination of image buttons and image controls - the buttons have a vertical line on the left and the item on the right (Form1, Form2, whathaveyou) that redirects to other pages.  Then between the buttons are image controls with the vertical line, to create the illusion that everything is one graphic.  When people with different privileges log in, different menu items are displayed, and sometimes in different places.  My problem is that this has caused me to overlap some of the controls slightly that are visible simultaneously.  When you click some of the buttons, as you click, a dotted outline appears around them, and sometimes the dotted outline obviously disappears behind another control.  This is purely an asthetic issue, but I really want for those dotted lines not to appear at all.  How do I make that happen?  I don't see any properties on the controls that seem to dictate this.

Thanks!

JP