Bug Dragging in editor creates "drag down" effect on first mouse move

When trying to look around (right-click + mouse move) or move objects (left-click + mouse move) the first time we move the mouse (ex: the first pixel) while having the mouse button pressed a "mouse drag down" motion is created even if I move the mouse horizontally.

The mouse offset is even more visible if we try to create a selection box (left-click + drag) on the scene viewer:


This is running on Arch + KDE Plasma 5.
I currently cannot try Gnome.

 

hi there, some of us are having trouble running the editor on arch. would you like to share some info here? http://forum.unity3d.com/threads/unity-on-arch-manjaro-linux.350315/