Version: 4.61 and 4.7p3 - binary version from launcher
OS - Windows 7
Repro:
- Open empty project
- Set UI Scaling to 1.2 (or anything > 1.0) see High resolution display support for editor - Feedback for Unreal Engine team - Unreal Engine Forums
- Make one of the 2d views visible (front/side/top)
- Use left mouse drag to create a selection rectangle
Notice that the rectangle does not follow the mouse pointer.
e.g
The red dotted line is where I actually dragged the mouse - the white rectangle is where it appeared.
Looks like selection rectangle is not taking the application scale into account.
Note also that in the 3d viewport selection does not work properly either clicks happen in the wrong place so its very hard to select anything (though its not as obvious without the rectangle)