Debian bullseye: touching the touch-screen with a finger does not click on objects in Qt/Plasma applications

I am testing Debian Bullseye on a Thinkpad X1 Yoga Gen 6, using a live cd with KDE and non-free drivers ([debian-live-11.5.0-amd64-kde+nonfree.iso](https://cdimage.debian.org/cdimage/unofficial/non-free/cd-including-firmware/11.5.0-live+nonfree/amd64/iso-hybrid/)) . I'd like to be sure that everything I need works before wiping the hard drive. Everything seems to work indeed, except that when I use a finger to touch objects or buttons, these are not clicked as expected, only selected at best. This seems to happen with anything related to plasma/Qt: - touching any icon on the plasma panel (including the application launcher) just places the cursor there; - touching buttons in KDE apps/settings dialogs selects them but does not click them; - touching menus in KDE apps unfolds them, but touching menu items just selects them (eg File -> New Tab in Konqueror). Situations where the **finger works as expected**: - everything on web pages (HTML buttons, HTML5 controls on eg youtube) - everything in non-KDE applications (eg Firefox) - window titlebar buttons (minimize/maximize/close) for **all** apps. The included Wacom digitizer pen always works as expected (touching an object clicks on it). Here are some infos that may be relevant: KDE Plasma Version: 5.20.5 KDE Frameworks Version: 5.78.0 Qt Version: 5.15.2

user@debian:~$ uname -a
Linux debian 5.10.0-18-amd64 #1 SMP Debian 5.10.140-1 (2022-09-02) x86_64 GNU/Linux
user@debian:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 11 (bullseye)
Release:        11
Codename:       bullseye

user@debian:~$ sudo Xorg -version

X.Org X Server 1.20.11
X Protocol Version 11, Revision 0
Build Operating System: linux Debian
Current Operating System: Linux debian 5.10.0-18-amd64 #1 SMP Debian 5.10.140-1 (2022-09-02) x86_64
Kernel command line: BOOT_IMAGE=(hd0,gpt4)/live/vmlinuz-5.10.0-18-amd64 boot=live quiet splash fsck.mode=skip persistence --
Build Date: 05 August 2022  08:00:36AM
xorg-server 2:1.20.11-1+deb11u2 (https://www.debian.org/support)  
Current version of pixman: 0.40.0
        Before reporting problems, check http://wiki.x.org 
        to make sure that you have the latest version.

user@debian:~$ lsmod|grep wacom
wacom                 131072  0
usbhid                 65536  1 wacom
hid                   147456  7 i2c_hid,wacom,usbhid,hid_multitouch,hid_sensor_hub,intel_ishtp_hid,hid_generic

Relevant dmesg lines:

user@debian:~$ sudo dmesg|grep -i wacom
[    2.483787] input: Wacom HID 5278 Pen as /devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-WACF2200:00/0018:056A:5278.0002/input/input15
[    2.483979] input: Wacom HID 5278 Finger as /devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-WACF2200:00/0018:056A:5278.0002/input/input16
[    2.484211] wacom 0018:056A:5278.0002: hidraw1: I2C HID v1.00 Mouse [WACF2200:00 056A:5278] on i2c-WACF2200:00
user@debian:~$ sudo dmesg|grep -i screen
[    2.245919] input: WACF2200:00 056A:5278 Touchscreen as /devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-WACF2200:00/0018:056A:5278.0002/input/input9

xinput and evdev:

user@debian:~$ cat /proc/bus/input/devices 

[...]

I: Bus=0018 Vendor=056a Product=5278 Version=0100
N: Name="Wacom HID 5278 Pen"
P: Phys=i2c-WACF2200:00
S: Sysfs=/devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-WACF2200:00/0018:056A:5278.0002/input/input15
U: Uniq=
H: Handlers=mouse2 event7 
B: PROP=2
B: EV=1b
B: KEY=1e03 0 0 0 0 0
B: ABS=1000d000003
B: MSC=1

I: Bus=0018 Vendor=056a Product=5278 Version=0100
N: Name="Wacom HID 5278 Finger"
P: Phys=i2c-WACF2200:00
S: Sysfs=/devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-WACF2200:00/0018:056A:5278.0002/input/input16
U: Uniq=
H: Handlers=mouse3 event8 
B: PROP=2
B: EV=b
B: KEY=400 0 0 0 0 0
B: ABS=260800000000003

[...]

user@debian:~$ xinput|grep Wacom
⎜   ↳ Wacom HID 5278 Pen stylus                 id=13   [slave  pointer  (2)]
⎜   ↳ Wacom HID 5278 Finger touch               id=14   [slave  pointer  (2)]
⎜   ↳ Wacom HID 5278 Pen eraser                 id=20   [slave  pointer  (2)]
user@debian:~$ xinput list-props 14
Device 'Wacom HID 5278 Finger touch':
        Device Enabled (188):   1
        Coordinate Transformation Matrix (190): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
        Device Accel Profile (319):     0
        Device Accel Constant Deceleration (320):       1.000000
        Device Accel Adaptive Deceleration (321):       1.000000
        Device Accel Velocity Scaling (322):    10.000000
        Device Node (311):      "/dev/input/event8"
        Wacom Tablet Area (363):        0, 0, 12064, 7540
        Wacom Rotation (364):   0
        Wacom Pressurecurve (365):      0, 0, 100, 100
        Wacom Serial IDs (366): 21112, 1, 3, 0, 0
        Wacom Serial ID binding (367):  0
        Wacom Pressure Threshold (368): 0
        Wacom Sample and Suppress (369):        2, 4
        Wacom Enable Touch (370):       1
        Wacom Enable Touch Gesture (372):       1
        Wacom Touch Gesture Parameters (373):   530, 235, 250
        Wacom Tool Type (374):  "TOUCH" (381)
        Wacom Button Actions (375):     "Wacom button action 0" (376), "Wacom button action 1" (377), "Wacom button action 2" (378)
        Wacom button action 0 (376):    1572865
        Wacom button action 1 (377):    1572866
        Wacom button action 2 (378):    1572867
        Device Product ID (312):        1386, 21112
        Wacom Debug Levels (380):       0, 0

It seems that touching the screen does produce the right event: when I touch the screen I see button press 1 and button release 1 both with xinput and with evtest

user@debian:~$ xinput test 14 
motion a=8704 a=4839 a=0 a=0 a=0 a=0 
button press   1 a=8704 a=4839 a=0 a=0 a=0 a=0 
motion a=8701 a=4836 a=0 a=0 a=0 a=0 
button release 1 

user@debian:~$ sudo evtest /dev/input/event8
Input driver version is 1.0.1
Input device ID: bus 0x18 vendor 0x56a product 0x5278 version 0x100
Input device name: "Wacom HID 5278 Finger"
Supported events:
  Event type 0 (EV_SYN)
  Event type 1 (EV_KEY)
    Event code 330 (BTN_TOUCH)
  Event type 3 (EV_ABS)
    Event code 0 (ABS_X)
      Value   8833
      Min        0
      Max    12064
      Resolution      40
    Event code 1 (ABS_Y)
      Value   1925
      Min        0
      Max     7540
      Resolution      40
    Event code 47 (ABS_MT_SLOT)
      Value      0
      Min        0
      Max        9
    Event code 53 (ABS_MT_POSITION_X)
      Value      0
      Min        0
      Max    12064
      Resolution      40
    Event code 54 (ABS_MT_POSITION_Y)
      Value      0
      Min        0
      Max     7540
      Resolution      40
    Event code 57 (ABS_MT_TRACKING_ID)
      Value      0
      Min        0
      Max    65535
Properties:
  Property type 1 (INPUT_PROP_DIRECT)
Testing ... (interrupt to exit)
Event: time 1668884040.469294, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value 770
Event: time 1668884040.469294, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 9293
Event: time 1668884040.469294, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 3886
Event: time 1668884040.469294, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1
Event: time 1668884040.469294, type 3 (EV_ABS), code 0 (ABS_X), value 9293
Event: time 1668884040.469294, type 3 (EV_ABS), code 1 (ABS_Y), value 3886
Event: time 1668884040.469294, -------------- SYN_REPORT ------------
Event: time 1668884040.471569, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 9282
Event: time 1668884040.471569, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 3888
Event: time 1668884040.471569, type 3 (EV_ABS), code 0 (ABS_X), value 9282
Event: time 1668884040.471569, type 3 (EV_ABS), code 1 (ABS_Y), value 3888
Event: time 1668884040.471569, -------------- SYN_REPORT ------------
Event: time 1668884040.477811, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 9279
Event: time 1668884040.477811, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 3896
Event: time 1668884040.477811, type 3 (EV_ABS), code 0 (ABS_X), value 9279
Event: time 1668884040.477811, type 3 (EV_ABS), code 1 (ABS_Y), value 3896
Event: time 1668884040.477811, -------------- SYN_REPORT ------------
Event: time 1668884040.488292, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value -1
Event: time 1668884040.488292, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 0
Event: time 1668884040.488292, -------------- SYN_REPORT ------------

So I assume the issue lies somewhere in the interaction with plasma/KDE/Qt (as GTK and HTML work as expected). So my question is, **how do I make sure that plasma/Qt/KDE process a screen touch as a mouse button left click** ? Can you help me debug this? PS: basic multi-touch that works: two fingers for right click and scrolling; inch-to-zoom works (emulating key press/release 37) but is tricky, you have to try multiple times. PPS: I have read that Wayland seems to have a better support of gestures, but I really don't need anything fancy, and I'd rather stick with Xorg because I'm too old to learn new things, and Wayland in Plasma seems [too young](https://community.kde.org/Plasma/Wayland_Showstoppers) .

user@debian:~$ echo $XDG_SESSION_TYPE
x11

**Edit**: Reading a bit more on wayland, I am now willing to give it a try, so far I had mixed experiences: touch and basic gestures work, including pinch-to-zoom, but at the cost of loosing some pen functionality; moreover it gets less responsive and buggy after some time. I plan to experiment more with it. Maybe the version in Debian unstable will be better.