[cyleigh]

I wish to traverse each group in my OG document. I have the following code:

tell application "OmniGraffle Professional 5"
	set myGraphics to graphics of (canvas of front window)
	repeat with g in myGraphics
		set myGroup to group of g
		if (myGroup is not missing value) then
			repeat with g1 in graphics of myGroup
				-- do some stuff
			end repeat
		end if
	end repeat
end tell

I get the result that "myGroup" is not defined; I thought the whole point of testing for missing value is to check for defined? (ie/ null check). The if statement doesn't work the other way either (ie, check for missing value).. what am I doing wrong?