Doug,
If you actually set the Control Mode (from the editor panel or by setting ATTR_CTRL_MODE) to Indicator, then the control won't highlight. Indicators are displayed differently by default, but if you are setting custom colors anyway, your panel should continue to look the same.
If you weren't already tweaking colors and didn't like the look of indicators, another option would have been to leave the control mode as Hot, but set the ATTR_NO_EDIT_TEXT attribute. This prevents the control's contents from being highlighted when made the active control.
Mert A.
National Instruments