Bug 145815

Summary:	Scrollbar is too thin and click area too small when KDE global scaling set to 200% or more
Product:	LibreOffice	Reporter:	Jackson Sul <bugs>
Component:	LibreOffice	Assignee:	Not Assigned <libreoffice-bugs>
Status:	NEW ---
Severity:	normal	CC:	m.weghorn
Priority:	medium
Version:	7.2.2.2 release
Hardware:	All
OS:	Linux (All)
Whiteboard:
Crash report or crash signature:		Regression By:
Bug Depends on:
Bug Blocks:	102495
Attachments:	Small scrollbar; only half is clickable and highlighted. Screencast on a 1920x1080 screen with QT_SCALE_FACTOR=2 Sample doc with many pages, used to create the screencast from comment 3

Description Jackson Sul 2021-11-21 19:35:48 UTC

Description:
On a hidpi screen (in this case a 4K screen) Libreoffice's scrollbar width is too thin, not matching any other programs. Furthermore, the area of the bar which can be clicked is even smaller than is graphically shown: this is extremely apparent in long documents (and sometimes only half the scrollbar will light up when highlighted).



Steps to Reproduce:
1. Open Libreoffice (say, Writer) using a hidpi screen.
2. Add many pages to a document.
3. Try to click on the scroll bar portion displaying the viewed area with the mouse.

Actual Results:
It is extremely hard to click on the scroll bar.

Expected Results:
Scroll bar should be easily clicked.


Reproducible: Always


User Profile Reset: Yes



Additional Info:
There are really two interrelated issues here.
The first is the width of the scroll bar is extremely thin.
The second is the difficulty of clicking on the bar itself, even when the mouse is perfectly positioned over what should be a clickable area.
I'm not knowledgeable enough to know if they these should be separate issues.

Tested on:
LibreOffice Writer 7.2.2.2
Kubuntu 21.10
4K Laptop screen

Comment 1 Jackson Sul 2021-11-21 19:36:55 UTC

Created attachment 176408 [details]
Small scrollbar; only half is clickable and highlighted.

An image of the small scrollbar, with only half of it being highlighted. The click-to-select area is even less than the width of the tiny bar.

Comment 2 Jackson Sul 2022-09-17 20:05:01 UTC

If the GTK VCL plugin is used instead of the kf5 VCL plugin (SAL_USE_VCLPLUGIN=gtk3), this issue does not occur.

Comment 3 Michael Weghorn 2022-09-23 06:27:16 UTC

Created attachment 182639 [details]
Screencast on a 1920x1080 screen with QT_SCALE_FACTOR=2

I can reproduce some odd behavior on a non-HiDPI screen (1920x1080 resolution) with environment variable QT_SCALE_FACTOR=2 set, s. attached screencast.

Not the whole area of the scrollbar behaves as expected when dragging and not the whole area is always highlighted when hovering over the scroll bar area.

As compared to the scroll bar thickness with scaling disabled, I wouldn't say that the painted area is unexpectedly small, however.

A workaround might be to use the middle mouse button, in which case scrolling happens right to the position that is currently being clicked.

Version: 7.5.0.0.alpha0+ / LibreOffice Community
Build ID: 64e4363527422c913151efab0c0d0c6b8c2256c8
CPU threads: 4; OS: Linux 5.19; UI render: default; VCL: kf5 (cairo+xcb)
Locale: en-GB (en_GB.UTF-8); UI: en-US
Calc: threaded

Comment 4 Michael Weghorn 2022-09-23 06:28:27 UTC

Created attachment 182640 [details]
Sample doc with many pages, used to create the screencast from comment 3