After upgrading from Gazebo 2 to Gazebo 7, shadows stopped displaying properly in my Gazebo worlds. At first it appeared that the shadows were not showing all-together, but then I noticed that they appear in the background at seemingly random locations as I zoom in and out. A screen shot of the standard Empty World with these random shadows is shown below. I am curious if anyone has had a similar experience and/or has any ideas what could be happening.

EDIT: Additional information:

1. Operating system: Ubuntu 14.04.5 LTS

2. Graphics card info:

     description: VGA compatible controller
     product: Sky Lake Integrated Graphics
     vendor: Intel Corporation
     physical id: 2
     bus info: pci@0000:00:02.0
     version: 07
     width: 64 bits
     clock: 33MHz
     capabilities: pciexpress msi pm vga_controller bus_master cap_list
     rom configuration: driver=i915_bpo latency=0
     resources: irq:127 memory:f0000000-f0ffffff
     memory:e0000000-efffffff
     ioport:e000(size=64)
   

3. Installation procedure: Switched from Gazebo2 to Gazebo7 using answer here