I have a document of 49000 words (269000 chars) in Ancient Greek and English. It has a lot of Comments in various places. I can only estimate the number but I would say a few hundred ( I don't know how to get a count of them ). If I check the View -> Comments box then typing is very very slow. If I turn off the check box typing is fine. I, of course, need the comments so the only workaround I have is to continue the work in a separate file.
BTW, the version above says 18.104.22.168rc but in fact the version report by LO is 22.214.171.124.
Producing a testcase should be a simple matter of creating a large enough document with a bunch of comments in it. I don't believe I can share the document I hit this on, so hopefully it's easy to repro. Let me know if not and I'll see if I can produce a document I can upload.
Unfortunately we can't find & replace text in comments, otherwise this would be enough to provide a testcase: https://wiki.documentfoundation.org/QA/Bugzilla/Sanitizing_Files_Before_Submission#Sanitize_file_text
Now you would have to unzip the .odt and find & replace inside the content.xml and zip again..
status NEEDINFO until valid test case is provided.
Created attachment 117980 [details]
document with comments
See attached comments.odt document. If slow-down is not noticeable then perform Tools | Update | Page format. You should then notice a significant slow-down in scrolling speed. Trying to enter text in a comment box makes LibreOffice unuseably slow (see editable comment box on 2nd page).
I confirm issue using LibO 126.96.36.199 under Win8.1 x64
I confirm it with LO 5.1
Version: 188.8.131.52 (x64)
CPU-Threads: 4; BS-Version: Windows 6.19; UI-Render: Standard;
Gebietsschema: de-DE (de_DE); Calc: CL
Created attachment 127115 [details]
Created attachment 149294 [details]
Callgrind output from master
Just took it from typing
Arch Linux 64-bit
Build ID: a2a762a9b6cad4ab0bb1b71b99aebc8c047c94d0
CPU threads: 8; OS: Linux 4.20; UI render: default; VCL: gtk3;
Locale: fi-FI (fi_FI.UTF-8); UI-Language: en-US
Built on 14 February 2019
*** This bug has been marked as a duplicate of bug 61558 ***