Bug 153399

Summary:	[UI] Vertical scrolling becomes unresponsive when hide columns option is used such that the background is visible
Product:	LibreOffice	Reporter:	Nial Burns <nialburns>
Component:	Calc	Assignee:	Not Assigned <libreoffice-bugs>
Status:	NEW ---
Severity:	normal	CC:	aron.budea, buzea.bogdan, nialburns
Priority:	medium
Version:	7.4.4.2 release
Hardware:	x86-64 (AMD64)
OS:	Windows (All)
See Also:	https://bugs.documentfoundation.org/show_bug.cgi?id=153985
Whiteboard:
Crash report or crash signature:		Regression By:
Bug Depends on:
Bug Blocks:	133619

Description Nial Burns 2023-02-05 20:34:17 UTC

Description:
If you select all columns, unselect a few columns, then use the "hide columns" option, everything will be hidden except the columns you select.
If you unselect so few columns that you can see the blank background behind the cells, libreoffice calc becomes extremely laggy. This issue ONLY happens if the blank background is either on screen or closely cut off by the edge of the window. Performance remains stable when only a few cells are visible, as long as the edge of the window cuts off the background.
This issue is also confined to the specific window where problems are occurring. If there are multiple spreadsheets open in different windows, only the spreadsheet(s) with the background visible will experience lag while the others will not.

Steps to Reproduce:
1. Open localc 7.4.4.1 or later
2. Select All
3. Deselect zero or more columns
4. Hide all selected Columns
5. If many columns are not hidden, ensure that some of the background is visible on screen
6. Observe lag when scrolling up or down

Actual Results:
Lag is observed when scrolling up or down

Expected Results:
No lag is observed when scrolling up or down

Reproducible: Always

User Profile Reset: Yes

Additional Info:
I tested every version on the archives until the bug went away to determine the earliest affected version, which is 7.4.4.1, however only 7.4.4.2 shows up on the version menu. Version 7.4.4.1 took almost an hour to download from the archives while the other versions I checked took only about a minute, so it would be nice to get that fixed as well. I included version info for both 7.4.4.1 and 7.4.4.2.

7.4.4.1 Version Info:
Version: 7.4.4.1 (x64) / LibreOffice Community
Build ID: 988f4a351a6fa8cf4bdf2bdc873ca12cf8cbe625
CPU threads: 16; OS: Windows 10.0 Build 19043; UI render: Skia/Raster; VCL: win
Locale: en-US (en_US); UI: en-US
Calc: CL

7.4.4.2 Version Info:
Version: 7.4.4.2 (x64) / LibreOffice Community
Build ID: 85569322deea74ec9134968a29af2df5663baa21
CPU threads: 16; OS: Windows 10.0 Build 19043; UI render: Skia/Raster; VCL: win
Locale: en-US (en_US); UI: en-US
Calc: CL

Comment 1 ady 2023-02-05 22:54:05 UTC

I have noticed this too.

We have to wonder whether this is somehow related to:

https://wiki.documentfoundation.org/ReleaseNotes/7.4

quotes:
* Calc now supports and uses 16384 columns ( http://llunak.blogspot.com/2022/03/enabling-calc-support-for-16384-columns.html ) . (Luboš Luňák, Collabora)

* Hidden columns/rows can have an indicator per View ▸ Hidden Row/Column Indicator tdf#128258 (Heiko Tietze, TDF)

among other items related to columns that were introduced in LO 7.4.


BTW, changing menu VIEW > Hidden Rows/Columns Indicator doesn't seem to influence the lag.

The lag is not "terrible" (i.e. not "unresponsive") in my system, but it is notable.

OTOH, I admit I don't really recall whether this lag was present before 7.4.4.

Repro in:

Version: 7.4.4.2 (x64) / LibreOffice Community
Build ID: 85569322deea74ec9134968a29af2df5663baa21
CPU threads: 4; OS: Windows 10.0 Build 19044; UI render: default; VCL: win
Locale: en-US (es_AR); UI: en-US
Calc: CL

and in:

Version: 7.6.0.0.alpha0+ (X86_64) / LibreOffice Community
Build ID: d8e6b488ceaff7c88856ebcfcfec14d2d8cd7652
CPU threads: 4; OS: Windows 10.0 Build 19044; UI render: Skia/Raster; VCL: win
Locale: en-US (es_AR); UI: en-US
Calc: CL threaded