It is because of these windows that pointers/A frame ladders come in handy.
You can put the point into the top corner of the window, then you can still hold on to the ladder while cleaning the window.
If you angle your ladder right you can still be in front of the window.
If you put your ladders up the side of the window you will be staing at a brick wall. If you lean, obviously you have the chance of falling off.