makeing a 2D polgon. converting it to a polygon mesh. go into edit object mode. i can use extrude edge to change/pull the shape only in the Y axis no matter what X,Y or Z constraint i use. if i change to face mode i can pull a face to any axis no problem.
the green guild may show that i am locked to the Z but it only changes in the Y.
Design 3D SE only has the Extrude Normal Tool available. So, what you are trying to do would require Design 3D CX with has the Extrude Element Tool that will allow the edge to be extruded along that active guide or grid axes.
You could get creative with the Edge Extrude (Normal) Tool and the Face Extrude (Normal) Tool along with some face and/or edge deleting, etc. Maybe a Fill here and there, depending on what shape the object will take.