Issue with Subdivide in 2.5 Having to use 2.5 for reasons I won't go into, I'm having an issue with subdivide affecting other unselected faces.  I wasn't having this issue before so I'm not sure what caused it to pop up.  Image:



I only want to subdivide the selected surface, not the others.  I'm not sure why it's cutting them into triangles, either.  Any tips?
2.5 can't handle N-gons

Subdividing a single face implies that each edge of its boundary is getting new edges and vertices too. This means that the faces in the neighborhood are increasing their edge count.

If the subdivision process brings the faces to have a number of edges, like in your case, greater than 4, you are creating an ngon.

N-gons has been supported only since 2.63 (see Release notes).
 Before that version only quads and triangles were handled. That's why you see the subdivision.