Bug 497076

Summary:	Multi-finger touchscreen gestures cause to enter a bugged "selection box" state
Product:	[Plasma] plasmashell	Reporter:	Cameron Smith <cameronsmith002>
Component:	Containment	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	normal	CC:	kdedev, nate, notmart
Priority:	NOR
Version First Reported In:	6.2.4
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Cameron Smith 2024-12-05 11:22:53 UTC

SUMMARY
A very similar (though not identical) bug to [482222](https://bugs.kde.org/show_bug.cgi?id=482222). When using 3-finger gestures on a touchscreen device, some gestures are not handled gracefully and the desktop enters a limbo state with a selection box permanently shown on screen.

Marco Martin's excellent work on 482222 (as well as upstream work on Qt in version 6.8.1 [here](https://bugreports.qt.io/browse/QTBUG-127821)) has made this state slightly more difficult to enter. Unfortunately, it still very much does exist and happens relatively frequently on my machine.

STEPS TO REPRODUCE
1. Open plasma desktop, do NOT start gestures on any open applications/widgets.
2. Begin 3 finger gestures on the desktop background in any direction (overview, grid mode, left/right virtual desktop).
- *Often a common way I've found it happens more frequently is on gestures with some slight spreading/unspreading of all three fingers through the motion. Might just be unlucky/irrelevant.*

OBSERVED RESULT
Plasma inconsistently enters a limbo state in which:
- A selection box is shown permanently on the screen, even if the screen is no longer touched.
- Optionally move the mouse/touchpad/trackpoint to see that the selection box is also permanently fixed to the cursor as it moves without holding down the RMB/LMB. This can only be removed by selecting a desktop icon or...
- Tap the screen once. The permanent selection box disappears, but the desktop enters 'edit mode' even if the touch event is extremely brief.

EXPECTED RESULT
Gestures should work normally without triggering this state.

OS VERSIONS
Arch Linux
KDE Plasma Version: 6.2.4
KDE Frameworks Version: 6.8.0
Qt Version: 6.8.1
Kernel: 6.12.1-arch1-1

HARDWARE
Lenovo ThinkPad T480s (touchscreen)
Intel i5 CPU/IGPU 8th gen
16 Gb ram

ADDITIONAL INFORMATION
The previous history of the touchscreen gesture issues can be found [here](https://discuss.kde.org/t/3-finger-gestures-on-touchscreen-bug/15956/11).

Comment 1 Cameron Smith 2024-12-09 01:56:31 UTC

Issue has been confirmed by other users on discuss.kde.org. I will post their experience with this bug verbatim:

>>Quote:
```
I have a little different take on this bug. First I can test it on a touchscreen device with a dual-boot system of: KDE Neon Unstable (Plasma 6.3 dev, qt6 6.8.0) and Arch/EndeavourOS (Plasma 6.2.4, qt6 6.8.1). My experience is different with the 2 install.
Here is my experience:

- first notice that the bug (3-finger lock selection and then eventually trigger edit mode) is present only in `Folder view` (icons on desktop) one can choose the Desktop (without icons) and then you don’t experience the bug but obviously it is not satisfactory
- For me the bug is triggered when switching from empty desktop (i use a tilling script for kwin) but far less since plasma/kwin 6.2.
- Before the switch to Edit mode was systematical now indeed when the bug is triggered you can see the mouse selection lock and 1 Tap enter Edit mode; but if you double tap then the Selection mode is cancelled, it is like you enter Edit mode and then exit. Again it is not satisfactory but more manageable.
- However I can say that it is worse on my Arch install than the KDE Neon, maybe due to some work on future kwin 6.3. There is one “new” bug I encounter on Arch that is not present no KDE Neon Unstable (further test needed): see below.

“New” bug
when switching desktop with 3-fingers gesture at some point I loose part of the single tap. I could not trigger some elements (menu, widgets, app launcher, in-app element/icon for ex in dolphin, link in browsers) but I still can focus from one windows to the other and move window around by selecting the titlebar. Then I need to logout/login to get back interface.
Beside `journalctl -f` give me line like this:

 `kwin_wayland[6217]: kwin_core: Detected a touch move that never has been down, discarding`

When testing unsetting some config in SystemSetting before posting (disabling krohnkite, Virtual Desktop animation and OSD), I think I identified the source. If I disable the VD change OSD I don’t encounter it. I suspect that the OSD window grab a tap and then you loose it.

Edit: I verify and the “new” bug is not present on my KDE Neon Unstable (plasma 6.3dev) even with OSD set and animation and krohnkite.
```

Comment 2 TraceyC 2024-12-11 22:35:27 UTC

I am able to reproduce the original issue described with the selection box on git-master

I am also able to reproduce the issue with three finger tap entering Edit Mode on git-master

If I quickly tap with three fingers and swipe:
- Sometimes the gesture works as expected and the virtual desktop is switched
- Sometimes I briefly see Edit Mode, but then the virtual desktop is switched.

If I just tap with 3 fingers in the middle of the desktop, it goes into Edit Mode more often than not

Comment 3 TraceyC 2024-12-11 22:37:21 UTC

Bug 483291 is specific to Edit Mode

Comment 4 Nate Graham 2025-01-16 17:56:08 UTC


*** This bug has been marked as a duplicate of bug 482222 ***