Axis have the wrong aspect ratio
 

I've seen your first screencast and the ratio of 1:1 between the x and y axis just seems fine.
But it doesn't on my computer. I've tested 1.01 and 1.1 beta 1. Both have the problem.
I set horizontal and vertical minimum to 0 and maximum to e.g. 5 for both of them.
The x value is more than 1 (1.5?) so when I draw a "square" from point 0/1 to 1/1 to 1/0 it should be a square but the outcome is a rectangle.

Sorry for the trouble here! The aspect ratio is controlled by the size and shape of your canvas as well as your tick mark settings, so if even if you have 1:1 marks the distances won't be correct unless you adjust your window size (or your margins). In OmniGraphSketcher 1.1 That window should snap to that 1:1 ratio, but the effect may be subtle if you're moving quickly.

This was too easy to think of that :)

I guess the Sketcher was designed for "economic numbers" in the first place. I use it for scientific reasons and that's why I care about such "tiny" things.

Thanks for your help.