Select the paint brush (or pencil or eraser etc.), select a brush size and click on where you want to start the line. Hold down the "shift" key and it'll make straight lines.
Quote from Silverracer :Select the paint brush (or pencil or eraser etc.), select a brush size and click on where you want to start the line. Hold down the "shift" key and it'll make straight lines. thanks :-) makes racing stripes alot easier and better looking^^