Steps to reproduce:

1. Open Unity;
2. Open attached project and 'test.unity' scene;
3. Drag 'Cube' prefab from Project tab either to Hierarchy or to Scene view.

Actual result:
Nothing happens (see attached gif video).

Expected result:
After dragging prefab should be placed to Hierarchy panel and to the Scene view.

Regression introduced in Version 5.3.0f2 (abe83398e3e8).

Reproduces on both OSX (10.10.5 and 10.11.1) and Windows (10).

Note: may be related to this bug fix: https://fogbugz.unity3d.com/default.asp?745191