Some sort of visual indication with numbers on the rows and columns of a map at the borders or outer edge, for easier reference or measuring.
I thought of this when trying to find the middle of a wall section, I had to count the squares - figure out the middle, then count the squares again to find out which one was #19.
The status bar located at the bottom of the editor window includes the corrdinates below the mouse as "Map x:<x-coordinate> y:<y-coordinate>".
r7209 improves the display of mouse and cursor coordinates in the status bar.