Strange behavior when using "Window options"

[waddlesplash]

1. Enter xmax/ymax 10, xmin/ymin -10. Apply it.
2. Add any function (e.g. x^2)
3. Switch to cursor tool and drag.

[yerich]

Looks like a variable isn't being updated. I'll take a look when I get the chance.

[yerich]

Should be fixed by #3