Button Changes Color but Action isn't Performed?

The script below runs and I can see the “cancel” button change color as if it is being clicked, but the “cancel” action is not performed

tell application “Illustrator CS”
activate
end tell
tell application “System Events”
tell process “Illustrator CS”
tell menu bar 1
pick menu item “Color Settings…” of menu “Edit” of menu bar item “Edit”
tell application “System Events”
tell process “Illustrator CS”
click button “cancel” of window “Color Settings”
end tell
end tell
end tell
end tell
end tell

I have tried other “buttons” on this window and the same result

Any Ideas?