same happens to me while im gaming on my Win 8.1 64 Bit Notebook. My workaround is klicking the right button to move the mouse pointer continously. However drag&drop an item in the inventory works fine.

On my main gaming rig, also Win8.1 64bit I don't have this problem. Moving the mouse pointer works fine.

The main difference between these two devices is that my notebook has a nvidia gpu with optimus enabled while my desktop is running on a ATI gpu.

Update: issue should be linked to 0000804