I am just getting started with Blender 2.67b and I am having one very annoying problem.  How do you join two editor windows?  The instructions are to drag from the upper left corner to the window you want to join and a gray arrow is supposed to appear but every time I have tired it, a new window appears.  Can anyone help?

          Jack

that is how to add a new screen

to remove a screen move the cursor to the edge of the screens between the 2 and right click

from there the hrey arrow shows up to select which to merge with which the arrow points to the screen to gat rid of

Or you can use the same area (the cross hatch marks top right) to merge one into the other. 

Good job,I appreciate your work because i have the same problem,but your post solve my problem.Thanks for sharing information,your information increase my knowledge.