Bug 1509059

Description of problem:
I have a huge presentation 200 slides that containing a lot of cross-reference to the different slides. When i try to open the document,  I can't use libreoffice for 50 minutes or longer. The CPU processing is stick to 1 core.  

When I remove/de-install: libreoffice-gtk3 and libreoffice-gtk2,then the processing time is reduced by 4 minutes, and i can use the user interface. The CPU processing is spread out to 2 cores.

So it looks likes that using the libreoffice-gtk3 modules, libreoffice will be limited to use 1 core for processing.


Version-Release number of selected component (if applicable):
libreoffice-gtk2-5.3.7.2-1.fc26.x86_64
libreoffice-gtk3-5.3.7.2-1.fc26.x86_64



How reproducible:
Create a hoge impress document with a lot of images and references. Try to open the and edit the document with and without libreoffice-gtk2 and libreoffice-gtk3.

See the differences between processing. 

Steps to Reproduce:
1.Create a huge impress (200 slides with a lot of cross references) document and save this one
2.Re-open and edit the document


Actual results:
- The user interface became unusable;
- The program is freezing for 50 minutes;
- The CPU utilization is high 100% 
- The libreoffice proces is stick to 1 core 

Expected results:
- The user interface is usable
- The CPU load is high
- The libreoffice proces is spread to multiple cores. 


Additional info:
The seems to be a lot of performance issues in combination of libreoffice-gtk2 and libreoffice-gtk3. Some are solved but not al.

See:
- https://bugzilla.redhat.com/show_bug.cgi?id=1303562
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=837356
- https://ubuntuforums.org/showthread.php?t=2322879