Comment 3 for bug 1671869

There needs to be 2 modes in which dx/dy work:
1. snap to grid
2. freehand

The reason for freehand is because if you're not on a grid, like rounded corners, and you need to make sure the narrowest point is at least X, you use the mouse to check, and it won't be precise enough if it's snapping to large grid points instead.

I've found that while editing footprints in Cairo, software would start behaving oddly, stop snapping to grid, or stop performing freehand, and also stop updating dx/dy values no matter where the mouse is moved although spacebar would update the dx/dy but no updates on mouse movement. I've also had bugs where select/delete would not work on a simple line, and I had to restart Footprint editor for the aforementioned problems to go away.