I just installed v0.18, and from the first start it behaves strangely. Immediately when I create new document (or open existing), the view starts to spin and zoom erratically. No problem with 0.17 on same machine.
I disabled animation from display settings, and tried all navigation styles. Tried also keys 0-6 to set view. PC was restarted and I even uninstalled and reinstalled FreeCAD, but no change, it keeps spinning.
I uploaded YouTube video to demonstrate this bug (sorry for small video)
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16110 (Git)
Build type: Release
Branch: (HEAD detached at upstream/releases/FreeCAD-0-18)
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Finnish/Finland (fi_FI)