[TerminX]

If you want to delete a wall, just drag the points together. Take care not to remove any sectors in this manner, or you will corrupt your map.

For example, if you have a couple of walls that looks like this (assume A, B and C are all wall points):

A------B------C

All you need to do is drag point B so that it is on top of point A, like so:

B-------------C

At this point, your two walls with 3 points is now one wall with 2 points.