Steps to repro

1) Set up Perforce server on network (Plastic SCM not tested)
2) Set up Perforce client (P4V) on local machine, connected to server
3) Download project from this bug, unzip
4) Add relevant files (Assets folder, ProjectSettings folder) to depot in P4V (no need to commit)
5) Open project in Unity 5.2.0p1 or greater
6) Open Version Control window
7) Connect to Perforce server
8) Open only scene in project
9) With nothing selected in Project window, observe Editor framerate is fine
10) Select an asset so it appears in Inspector
11) Observe framerate/responsiveness of Editor is greatly reduced when navigating in Scene window, and lots of console spam is produced