Problem: ESnaps, selection and holding shift.

I have Draftsight installed on a laptop and a desktop. They behave differently and I can't work out why. Both versions are the same, and I have gone through all the options and preferences I can find. As far as I can see they are the same, and I've gone to the extent of exporting preferences from one and importing to the other, to no avail.

On the laptop, if I have any objects selected, I can draw a selection box (blue or green) on a blank area of the model space and that will deselect the previously selected objects. On the desktop, nothing will happen and to deselect I have to press escape.

On the laptop, if I am moving say a line, then I can hover over another point to activate the ESnap, hold shift to move the line orthographically, and move it to the intersection with the vertical or horizontal guide line that comes from the ESnap point. On the desktop, I can pick up the ESnap point and move the line to intersect the guide line, but as soon as I hold shift the guide line disappears and I can't snap to it.

It's pretty irritating having to remember these foibles when switching machines, and I'd love the desktop to work like the laptop, as I feel that's more intuitive. i expect there's some simple setting that I've missed, so I hope someone knows what it is!