Since GraphicConverter doesn't have a scriptable color wheel I kludged the following.
set black to {"0", "0", "0"}
set blueGray to {"8000", "8000", "10000"}
set white to {"65535", "65535", "65535"}
set red to {"65535", "0", "0"}
set theColorList to {"Black", "blueGray", "White", "Red"}
tell application "GraphicConverter"
activate
set {theChoice} to choose from list theColorList default items "blueGray" with title "Color Selection"
if theChoice = "bluegray" then
set theChoice to blueGray
else if theChoice = "black" then
set theChoice to black
else if theChoice = "white" then
set theChoice to white
else if theChoice = "red" then
set theChoice to red
end if
-- display dialog theChoice as text
show tools
tell window 1 -- Tools window
set background color to theChoice
delay 0.2 -- need time
end tell
end tell
TIA,
Robert Poland - Fort Collins, CO