Questions regarding color problem in AutoCAD Mechanical 2007

Hi everyone,

In AutoCAD Mechanical 2007 I'm having a problem with colors. When I
change the color of a 3D solid model part within an assembly, save the
drawing, then open the drawing again, the part seems to revert back to
previous colors that were used during the design process.

Sometimes, a part is even more than one color, one surface may be
blue, another surface may be red, etc.. It seems AutoCAD is
*remembering* all the colors that I tried or used throughout the
design process and is somehow getting confused as to which color was
the last saved color.

The drawing has a fair number of layers and I wonder if the issue is
somehow related to layers. If I type the layer command and change the
color for the part there, and then go to "object properties" and
choose "by layer" as the part color, it does not help. Additionally,
if I actually choose for example *red* from object properties, I still
have the problem.

I can change colors fine while the drawing is open, but when I save
the drawing and reopen it later, some parts are either not the color
that was last saved, or some parts have several surfaces with
different colors (colors that were used or tried throughout the design
process).

It may be worth noting that when the drawing opens, for the first few
seconds the colors seem correct, then a few seconds later, the colors
of certain parts within the assembly will change.

When you add or subtract to or from a solid model part, does the
portion that is being added or subtracted have to be on the same layer
and/or be the same color as the part that is being modified ? I never
had to worry about this with previous versions of AutoCAD but perhaps
something changed.

I would appreciate any ideas or suggestions anyone may have.

Thanks
John