3-Finger Gestures on Touchscreen Bug

Hi all,

I’ve found a bug that I can easily replicate on every bootup of my machine that flummoxes me: When using 3-finger swipes to switch desktops or open overview on my touchscreen, edit mode is entered (initially) and subsequent attempts to use 3-fingered gestures cause a selection rectangle to be opened on my desktop (wherever the mouse is positioned).
Note that this is NOT an issue with touchpad gestures (flawless), just my touchscreen.

A lot of words here to describe a weird problem: To reproduce on my laptop:

  • #1: Use 3f gestures on touchscreen → enter edit mode
  • #2a: Exit edit mode, try to use gestures again → edit mode is not entered, but a selection rectangle is permanently shown on the desktop which follows the mouse (even without pressing either mouse button).
  • #2b: (Notably, once this selection rectangle is present, 3f gestures on the touchscreen are flawless.)
  • #3: Only way to remove this selection rectangle is to either log out or to use the selection rectangle to “actually” select something on the desktop. This does remove it, however…
  • #4: Once the selection rectangle is removed, using 3f gestures on the touchscreen begins step #1 all over again.

My hardware/software specs:

  • Wayland session

  • Plasma: 6.0.4

  • KDE framework: 6.2.0

  • Qt version: 6.7.0

  • OS: Arch linux, 6.9.1 kernel

  • T480s Thinkpad

  • CPU: intel i5-8th gen

  • GPU: intel Mesa UHD 620

  • Ram: 16Gb

Any ideas/input would be much appreciated! Not sure if this is a plasma issue or a thinkpad screen issue.

Smathles

1 Like

I’ve got the same problem!

Thanks for pointing out that it disappears when selecting an item on the desktop.
I had nothing on my desktop, but once I put something I can confirm it works.

I removed it using other multi-finger gestures (4 and 5 fingers).
But, I cannot do it successfully every time.
I’m not sure what triggers it to exit out of the “selection” state.

kwin_wayland --replace & also does the trick, but it’s by no means a solution.

System Info:

Lenovo Yoga 7
OS: Manjaro Linux x86_64 
Kernel: 6.1.90-1-MANJARO 
KDE Plasma Version: 6.0.4
KDE Frameworks Version: 6.1.0
Qt Version: 6.7.0
Graphics Platform: Wayland
Graphics Processor: AMD Radeon Graphics
Processors: 12 × AMD Ryzen 5 5600U with Radeon Graphics
Memory: 16 GiB of RAM

Good to hear it’s not just me hallucinating :skull:! Generally, I don’t keep icons on the desktop (krunner was made for a reason lol) and like that aesthetic, but as long as this is a bug, might keep a photo there to get rid of this issue.

Possible note for devs/others troubleshooting is we both use lenovo touchscreens? It would be nice if someone else can replicate this on a non-lenovo laptop setup!

Update: This is bug 482222. According to Nate, it seems to possibly be because “the gestures aren’t being exclusively captured by KWin”.

So it’s a confirmed Kwin bug, not just a weird hardware issue on my end it seems.

1 Like

Bug Detail Update:

I haven’t tried fixing or debugging this issue (kwin stuff is beyond me), but I noticed an interesting detail: 3-finger gestures to move to different virtual desktops are perfectly functional as long as the gesture is performed on top of an application, not the plasma desktop background/wallpaper area!

To replicate this, have at least 2 adjacent virtual desktops with maximised application windows open. 3-finger gestures now work perfectly!

Notably, this even works with non-maximised windows as long as the gesture is not started on the desktop!


For example, in the above image:

  • If I start a 3-finger gesture on the terminal window, virtual desktop switching/overview/grid display is flawless.
  • If I start a 3-finger gesture on the task manager/lower bar (tricky, but doable), virtual desktop switching/overview/grid display is flawless.
  • If I start a 3-finger gesture anywhere on the desktop background/wallpaper area, the issue immediately appears with symptoms as per bug 482222!

So this additional info is perhaps not “riveting stuff”, but IMO all debug information is helpful for those fixing bugs! I’ll update the bug report now as well.

Thanks for the report and the trick to select item on the desktop. I was going to post/report when I saw this. Notice that the lock selection bug is only trigger when the layout in the Desktop settings is on Folder view and not on Desktop (no selection then).
And when I do the trick to select an item when the lock selection is triggered and then I tap on the desktop it enter in Edit mode again.

By the way did you know if there is a report for the 3 fingers swipe behavior? The actual situation is messy, in particular Edit mode triggered every time I use 3f on desktop I know we like to configure on kde but … I don’t change my layout itch time I change virtual desktop. Personally, I would prefer the touchscreen gestures to be more coherent with that of the touchpad. I work on a 3x3 grid and I miss switching VD vertically. And 4 finger could trigger grid view/Overview.

As I understand it, customisable gesture support using libinput is planned (GitLab issue here), but not yet implemented in KDE 6.

Bug 482222 kinda sucks on touchscreen devices tbh, but not really a critical issue for most users without a touchscreen. Fortunately, it’s had enough bug duplicates to make it into the “15 minute” bugs page (here) that’s constantly on the dev team’s radar!

I note that GN*ME has touchscreen support for 3 finger left-right swipe for workspaces working perfectly in wayland, but of course GN*ME does not support workspace grids and iirc has no intention to. So that may not be useful for your current needs.

I would love to get more customisation options for gesture customisation in Plasma 6 soon. I personally don’t have a use for grid workspaces, so I’d like to rebind “grid” and “overview” to 3-finger swipe on the touchpad instead of 4.

[Pure speculation warning:] this a feature that might take a bit more time though, as there’s a fair few other enchancements like mouse gestures and multi-monitor workspace overhauling that I think may be focused on first.

There seems to be more interest for touchpad gesture than touchscreen. And there is interest in improving the scheme of gesture but the fact that any 3 fingers gesture start by entering Edit mode is more of a bug and I think it could easily be removed. It double the long tap 1 finger that trigger Edit mode and in fact, as someone said, it is in the context menu and it might be more useful to open the context menu with a gesture and enter Edit mode from there.

Right now it so annoying that I put konsole windows here and there to avoid Edit mode. I don’t even now if people really use Edit mode this way so often.

Obviously customizable gesture would be great and satisfy everyone needs. But it seems that it is not for today. I would think that a coherent scheme with reasonable gesture could be good. Personally I haven’t strong opinion on it. The grid desktop layout is one thing that brings me to kde (from sway) .

I don’t plan to change (and not for Gnome), but I appreciate if up/down gesture for vertical desktop switching could be implemented. It could be with 4 fingers swipe if ppl prefer to keep 3f for overview (that I don’t use), I could live with that it particular if custom gesture is implemented in the future. You even could have 3f triggering overeview/grid up/down and desktop switching left/right and 4 fingers to switch desktop in 4 directions so you have both possibility, until customization is there.
4 fingers seems to be the mac way so maybe some people expect that.

1 Like

For future internet necro-stalkers, this issue was fixed in Plasma 6.2
:slight_smile:

Update: This issue has only been improved. Bug 482222 is has been seemingly resolved on KDE’s end, but I still experience problems. However, Qt as of 6.7 still has an upstream bug and I experience the following (slightly different from before):

  • three finger gestures, but do the gesture in any direction while spreading and contracting fingers as if it is a pinch and zoom. Sometimes while doing this, a blue “selection” rectangle will open, but remain on screen if I remove my fingers.
  • After this, try using mouse/touchpad and see that the box is clipped to my cursor even without pressing the LMB. Even pressing the LMB will just spawn the blue selection box in a different location under the cursor.
  • Just as before, this will only go away if I select a desktop shortcut.
  • However, I have also discovered that if I then tap the touchscreen again while in this buggy state, the selection box disappears and the desktop enters edit mode, regardless of how long I tap the screen (even instant taps set this off).

Was the previous bugfix in vain? I don’t think so. My current arch setup (hardware specs above) is currently at:

  • Plasma 6.2.3
  • KDE Frameworks 6.8.0
  • Qt Version 6.8.0
    Importantly, according to Qt’s official bug report, this was only fixed in Qt 6.8.1. So I’m hoping this will be fixed when plasma upgrades their Qt version!

Will report back when Qt upgrades and I get an opportunity to test it!

Hi everyone,

Today I finally was able to upgrade plasma on arch to Qt 6.8.1 where the relevant Qt bug should be patched as per this report. Unfortunately, even after this upgrade and a restart, the bug still seems to be present. Though possibly a few subtle aspects of the bug have changed over the course of a few months, it actually feels just as bad if not very slightly worse than before.

Bug conditions are exactly the same as illustrated earlier, though I additionally note on rare occasions if:

  • Screen is filled with windows (let’s say fullscreen terminals on each workspace to avoid touch + desktop issues).
  • Rapidly cycling through desktops with 3-finger gestures mostly works, but sometimes “flickers” in and out and fails to render the terminal window for an instant. In these cases, 2 virtual desktops are switched with one gesture instead of 1.

Here’s my specs, note the phantom selection area on the screen (gained by touch events as described earlier, no mouse cursor to be seen → it’s just a touch screen thing).

I will see if I can write a new bug report later on today.

Current bug report to follow: 497076 – Multi-finger touchscreen gestures cause to enter a bugged "selection box" state

1 Like

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.

Thanks for verifying again @alioth9. I’ve updated the bug status as ‘confirmed’ and appended your comment. Hopefully this can get pushed to the “15 min” bugs list, as it’s really a deal-breaker for touchscreen-dependent users and very easy to run into.

I’m ok on a laptop w/ a trackpad, but I imagine it could make things very difficult on a tablet or all-in-1 laptop.