Comment # 2 on bug 947782 from Boian Berberov

My bug is very similar so I'll continue here.

I'm running:
- openSUSE Tumbleweed up to date
- Intel Sandy Bridge with Nvidia Optimus which should be disabled

In my case the primary reason for the high CPU is having FolderView widgets on
the desktop.  The bug is definitely reproducible and consistent.

I use a desktop with a "Desktop Containment" layout.  When the desktop is bare
and has no FolderView widgets, CPU usage is normal.  Add two or more (one works
too, but the results are not as dramatic) FolderViews and restart the system,
not just X!  After logging back in, CPU usage for plasmashell is +50%, but may
be as high as 100%.  Remove the FolderViews and restart, CPU usage goes back to
normal.

This started happening sometime in June 2017 and may be related to Qt 5.9.  I
don't keep very close track of changes so I cannot be sure.

If you tell me how to use strace on plasmashell I'll post traces.  I don't have
much experience with it.  Thanks.