Trouble moving windows in blender around


So what do they call it when the double arrows show up so you can move a window size.?
Any way to control the area that makes it chage to double arrows so its not so difficult to move a window. ? If I knew what they called that I would at least have a chance to figure out how to ajust it.
Thanks

I think it’s called resizing the window. There may be a technical term.