How do I change the colour of the non-scrolling region and background of WinHelp?

The Media object controls the non-scrolling region and background colours for Winhelp

In the topic you wish to change this for, select the Windows Help tab
Select the Display and Contents secondary tab
The Help Window field, determines which Media object the topic uses
They will probably be the Media Objects called "Procedure Window Template" and "Reference Window Template"
Now open the Media Template object your Topic is based on
Select Windows help tab
Select Colour tab
Select the Change button to set these colours