Hi Craig,
Yep, already checked that for all the toolpath windows (On the Program Run, Tool Path and Machine Diagnostic windows) and they are all enabled. Apart from the size and position,the only other difference was the Enabled States, so I made them all the same (All), but this made no change and the only one that displays as it should is the "Tool Path ops" .
More info that may help is if I change the Bg Colour in Screen Edit mode, the new colour is applied whilst still in Edit Mode, but when I save the change and exit Screen Edit, the new colour is not applied!
Nick.