The easiest way is to change the Color parameter to use "Color By Expression" option:
In my sample QVF (attached), I am checking the company name and forcing system to use a bright color (RGB(255, 0, 0)) for this segment. All other segments are painted with dark colors...
if (index(company, district) >= 1, rgb(255, 0, 0), rgb(Rand()*90, Rand()*90, Rand()*90))
This is a simplified way and you might have more complex structure to map the company to the district.
I am not sure what requirements do you have, but I am sure you can update this algorithm to use any other conditions to select your colors.
Pie Chart Test.qvf 176.0 K
Here is my example (see attached file).
I need to paint the selected region as red on pie chart (see color by expression), can you help me to do that?
It works when I select Response filed (click with a mouse)
But i need it to work when I select CLnum row in table.
UPDATE: solved it.
Pie Chart Test.qvf 192.0 K