Dear Most of you who know much more than I do about Blender:
I am using the extrude tool (E) on my Mac osx, Blender 2.5.
The extrude tool started out today working exactly as described in the various online tutorials. Now, however, it by default extrudes only along the Z axis. I have to click Z again to un-constrain the extrusion. I have exited Blender and reopened. It remains unchanged.
How can I remove this annoying default constraint so I can freely extrude?
Thank you kindly for considering my small question.