I'm playing in 1600x900 windowed mode on a 1920x1200 resolution monitor.

When it's my dudes turns, they won't be able to move until I zoom in with the mouse wheel, then zoom back out.   At that point, the movement interface becomes available and I can move them.  If I don't zoom in, the movement interface will not come up and they can't move.

This also happens if I play in fullscreen 1920x1200 resolution.

hmm, I haven't seen that myself or heard anyone else mention it but I will see if we can reproduce it!

Was it on the tutorial mission? did it happen on any other missions. any additional details you can think of that might help? 

Yes, on the tutorial mission.  I haven't tried any other missions yet.  I will, though, and update this message.

[edit] Still in the tutorial and my movement interface will also appear if I scroll the map with WASD or right-click mouse scroll.  Before that, no movement interface.

[edit again] Ok, this happens in first mission after the tutorial, too.  So, it's not just a tutorial thing.  I NEVER get the move UI until I scroll the map or zoom in/out.  Frustrating.