How to create expand/collapse threads on "Messages"

Content

Hi everyone! 



Hope you can assist me with the report I'm attempting to create, regards to the title of this topic.



Based on this idea , and our own company needs I've begun creating a report to have the ability to expand/collapse threads. 



When responding back to a incident, the formatting looks fine and everything (see attachment "Incident 160401-000365"). 

However, when opening the report - it shows some formatting that I would like to have removed (see attachment "Incident 160401-000365 - report")



In the report, I've selected to "strip HTML tags" - but still, they appear in the report.