gnome-shell using 100% CPU

Question

I am running Fedora 21 on my Lenovo X1 3rd gen and I noticed that the process gnome-shell uses 100% CPU almost all the time.

I found that this could be due to a missing graphics driver but this does not seem to be the case. Here is the output of lspci -vnn | grep VGA -A 12:

00:02.0 VGA compatible controller [0300]: Intel Corporation Broadwell-U Integrated Graphics [8086:1616] (rev 09) (prog-if 00 [VGA controller])
Subsystem: Lenovo Device [17aa:2227]
Flags: bus master, fast devsel, latency 0, IRQ 52
Memory at f0000000 (64-bit, non-prefetchable) [size=16M]
Memory at e0000000 (64-bit, prefetchable) [size=256M]
I/O ports at 3000 [size=64]
Expansion ROM at <unassigned> [disabled]
Capabilities: <access denied>
Kernel driver in use: i915
Kernel modules: i915

From what I understand, OpenGL is working fine as well. glxinfo | grep OpenGL reports:

OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) HD Graphics 5500 (Broadwell GT2) 
OpenGL core profile version string: 3.3 (Core Profile) Mesa 10.4.3
OpenGL core profile shading language version string: 3.30
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 10.4.3
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.0 Mesa 10.4.3
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.0