COM Control (color) color management error when embedded in PowerBuilder

We have created some .NET controls and we are using them as COM controls in the PowerBuilder application .

They (mostly) consist of controls with other controls on them, some of our other custom controls, some of DevExpress. All of ours inherit from a common base - and this has a DevExpress LookAndFeel control to ensure that we can easily change the look of the entire application in one layer if needed (we should have done this twice already!).

The BackColor for all controls is set to the Control system color and displays correctly in that color (gray for Windows 2000 by default) when the controls are embedded in our .NET test forms.

When controls are built into PowerBuilder, they do not display correctly and the back color appears white.

Is this a PowerBuilder bug? If so, what is the solution? If not, what do we need to do to correct the situation? (while still being able to have all controls that match the schematic without individually setting each BackColour).