Bug 158562

Summary: EDITING: Cursor movement and typing out of sync preventing work in complex documents
Product: LibreOffice Reporter: krassowski.michal
Component: WriterAssignee: Not Assigned <libreoffice-bugs>
Status: UNCONFIRMED ---    
Severity: normal CC: ilmari.lauhakangas
Priority: medium    
Version: 7.6.2.1 release   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
Crash report or crash signature: Regression By:
Attachments: A GIF demonstrating the cursor lag after pressing arrow left and incorrect text as a result
Impact on formatting: double-click first word & press ctrl + i (works), double-click second word & press ctrl + u (nothing happens), double-click third word & press Backspace (gets underlined deleted)

Description krassowski.michal 2023-12-06 11:51:10 UTC 
Description:
There is a delay of up to 20 seconds between the request to move the text cursor/caret (pressing Left/Right/Up/Down arrow keys, or Backspace or Delete or selecting/putting a cursor with mouse pointer) and the change taking place; because Writer treats the typed characters asynchronously from the selection/cursor position this leads to the core functionality - writing - being not usable in the large document.

For the past few months I was writing in gedit and copy-pasting chunks. The bottleneck is though that if I want to perform any formatting or replace existing text I need to select things and this takes many seconds/is not reliable.

Steps to Reproduce:
1. Open a large, complex document (50k+ words, hundreds citations, many figures, a few footnotes - basicaly a doctoral thesis which I cannot share yet)
2. Type "qwerty"
3. Press left arrow key
4. Type "aaaaa"

Actual Results:
"qwertaaayaa"

Expected Results:
"qwertaaaaay"


Reproducible: Always


User Profile Reset: No

Additional Info:
This appears distinct from issue 133137 because that issue describes problem with typing alone. For me typing works perfectly (as long as I do not press backspace or ever make an error which sadly is not that long).

This appears distinct from issue 153828 because switching to SAL_USE_VCLPLUGIN gen or SAL_USE_VCLPLUGIN kf5 does not fix it.

This appears distinct from issue 148433 because I do not use both RTL and LTR characters and it affects all paragraphs alike.

This is not caused by the number of words alone - I created a document with 100k words using Lorem Ipsum and the issue was not there.

I tried dissecting the problem by splitting my thesis into smaller chunks (it was already happening at a single chapter level) but I could not narrow it down to a single feature (like figures/tables/references) just yet.

This is not a regression in the recent release - it was like this in previous version (7.5) too. I will try to test older versions soon.
Comment 1 krassowski.michal 2023-12-06 11:57:30 UTC 
Created attachment 191264 [details]
A GIF demonstrating the cursor lag after pressing arrow left and incorrect text as a result
Comment 2 krassowski.michal 2023-12-06 12:03:26 UTC 
Created attachment 191265 [details]
Impact on formatting: double-click first word & press ctrl + i (works), double-click second word & press ctrl + u (nothing happens), double-click third word & press Backspace (gets underlined deleted)
Comment 3 krassowski.michal 2023-12-06 12:10:14 UTC 
Of note, direct cursor mode is diabled and enabling it does not help either.

I would not mind having the delay in typing as long as I can continue typing and know that the key sequence that I pressed will be reflected in the document.

This is not a problem with the machine being slow (64 GB RAM, pretty fast CPU with 12 cores, 24 threads) - the resource usage is minimal when typing or moving cursor/selection.
Comment 4 krassowski.michal 2023-12-06 12:21:37 UTC 
Correction, switching to SAL_USE_VCLPLUGIN=gen does appear to mostly fix it (while selection across paragraphs is stil slow, typing and modifying cursor position is now reasnably fast). SAL_USE_VCLPLUGIN=kf5 does not make a difference for me.
Comment 5 Buovjaga 2024-01-17 17:28:44 UTC 
Was this seen under a Wayland or X11 session?