Bug 396442

Summary: Hard to tell when window preview list is scrollable, and hard to trigger scrolling
Product: [Plasma] plasmashell Reporter: David <david.cortes.rivera>
Component: Task Manager and Icons-Only Task ManagerAssignee: Eike Hein <hein>
Status: RESOLVED FIXED    
Severity: minor CC: bugseforuns, codestruct, iodreamify, nate, plasma-bugs, postix
Priority: NOR Keywords: junior-jobs
Version: 5.13.2Flags: hein: Usability+
hein: VisualDesign+
Target Milestone: 1.0   
Platform: Debian unstable   
OS: Linux   
Latest Commit: Version Fixed In: 5.22
Sentry Crash Report:

Description David 2018-07-12 14:23:29 UTC
If I open enough instances of some application so as to fill up the preview space on a screen - that is, the small previews that are shown when pointing the mouse at some application icon in the icons-only task manager for example - only the instances that fit into the screen resolution are shown, instead of being grouped into rows and/or shrunk to fit into the screen.

Steps to reproduce:
* Set task manager to icons-only task manager.
* Configure it to show window previews when pointing the mouse at icons (right click on the task manager -> Configure Icons-only Task Manager -> tick "Show tooltips").
* Open a lot of instances of some application (e.g. launch dolphin 20 times).
* Point the mouse over the application icon (of which many instances were launched in the previous step) until it shows the window previews.

Expected behavior:
* Should arrange all the windows in a smart way to display them all in the available screen space.

Actual behavior:
* Starts arranging them into one row, displaying only the ones that managed to fit into it.

Reproducible: always.
Comment 1 Eike Hein 2018-07-12 14:36:09 UTC
It's scrollable. Changing this is possible but it's the VDG's call.
Comment 2 Nate Graham 2018-07-12 14:44:51 UTC
Tricky issue. Maybe instead of making it scrollable, we could add another row/column? Pretty niche use case though.
Comment 3 David 2018-07-12 15:29:28 UTC
(In reply to Nate Graham from comment #2)
> Tricky issue. Maybe instead of making it scrollable, we could add another
> row/column? Pretty niche use case though.

I wouldn't call it a niche use case. With a screen resolution of 1920x1080, which I guess it's today's most common setup, it takes barely 7 windows to fill the preview row. And for me at least, it doesn't scroll (tried rolling the mouse wheel and moving the mouse towards the end of the row).
Comment 4 Gregor Mi 2018-07-16 21:32:08 UTC
Currently, you can scroll with "Mouse left click plus Drag left/right".
Comment 5 David 2018-07-17 07:23:47 UTC
(In reply to Gregor Mi from comment #4)
> Currently, you can scroll with "Mouse left click plus Drag left/right".

Can confirm this works now. Although, I think it is a rather unintuitive form of scrolling.
Comment 6 Nate Graham 2018-07-17 14:16:49 UTC
Click-and-drag works fine for touch where it becomes the familiar tap-and-drag gesture, but it sounds like we need the following changes here to improve the user experience:

- Always show a visible scrollbar if there are more windows than fit in the screen at once (this is one of the primary purposes of visible scrollbars, in fact)

- Allow the list to scroll horizontally when using the mouse wheel without having to add a modifier key.
Comment 7 David 2018-07-17 17:21:46 UTC
(In reply to Nate Graham from comment #6)
> Click-and-drag works fine for touch where it becomes the familiar
> tap-and-drag gesture, but it sounds like we need the following changes here
> to improve the user experience:
> 
> - Always show a visible scrollbar if there are more windows than fit in the
> screen at once (this is one of the primary purposes of visible scrollbars,
> in fact)
> 
> - Allow the list to scroll horizontally when using the mouse wheel without
> having to add a modifier key.

While this seems like a reasonable idea, IMHO, grouping into rows would look better and allow finding the right window faster.
Comment 8 Nate Graham 2018-07-17 17:47:37 UTC
Yeah, that could also work. Seems like we have a few good options here.
Comment 9 Nate Graham 2021-04-07 09:27:20 UTC
Git commit 2275a4771067a95cab17999db0ad1f90d392eae4 by Nate Graham.
Committed on 07/04/2021 at 09:26.
Pushed by ngraham into branch 'master'.

[applets/taskmanager] Use a PlasmaComponents3 ScrollView for tooltip

This gives us a functional scrollbar for free.
FIXED-IN: 5.22

M  +2    -5    applets/taskmanager/package/contents/ui/ToolTipDelegate.qml

https://invent.kde.org/plasma/plasma-desktop/commit/2275a4771067a95cab17999db0ad1f90d392eae4
Comment 10 iodreamify 2022-12-07 15:47:38 UTC
(In reply to Nate Graham from comment #6)
> Click-and-drag works fine for touch where it becomes the familiar
> tap-and-drag gesture, but it sounds like we need the following changes here
> to improve the user experience:
> 
> - Always show a visible scrollbar if there are more windows than fit in the
> screen at once (this is one of the primary purposes of visible scrollbars,
> in fact)
> 
> - Allow the list to scroll horizontally when using the mouse wheel without
> having to add a modifier key

On Plasma 5.26.4 and qt 5.15.7 when the thumbnail list is full and the horizontal scrollbar is shown i can't scroll with the mouse wheel, even if the mouse is directly on the scrollbar.  

Previously i used to be able to scroll with drag and drop as described above but now it's no longer the case. The only way to scroll is to drag the scroll bar with the mouse. Is this a bug related to this or should i open a new bug report? Mouse wheel horizontal scrolling does work in other apps.
Comment 11 Nate Graham 2022-12-07 19:51:21 UTC
Does it work if you hold down Shift or Alt while you roll the mouse wheel?
Comment 12 iodreamify 2022-12-08 00:07:05 UTC
(In reply to Nate Graham from comment #11)
> Does it work if you hold down Shift or Alt while you roll the mouse wheel?

On Wayland nothing works.
On X11 scrolling while holding down Alt while hovering over the thumbnails works.
Comment 13 Nate Graham 2022-12-14 21:53:50 UTC
Can confirm that with a horizontal panel (a vertical panel works).

That's a separate bug though; can you file a new one?
Comment 14 iodreamify 2022-12-15 00:52:03 UTC
(In reply to Nate Graham from comment #13)
> Can confirm that with a horizontal panel (a vertical panel works).
> 
> That's a separate bug though; can you file a new one?

Done:  https://bugs.kde.org/show_bug.cgi?id=463054