Created attachment 141591 [details]
Recording of the events
Under Windows, as well as on my old laptop, when I click on the touchpad and keep it "clicked" with one finger, I can then drag the object with my swiping with my other finger. On T480s it doesn't work. The cursor doesn't move at all,
although I can see it changing shape when the drag happened on the top bar of a window.
Device 'Elan Touchpad':
Device Enabled (174): 1
Coordinate Transformation Matrix (176): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
libinput Tapping Enabled (328): 1
libinput Tapping Enabled Default (329): 0
libinput Tapping Drag Enabled (330): 1
libinput Tapping Drag Enabled Default (331): 1
libinput Tapping Drag Lock Enabled (332): 0
libinput Tapping Drag Lock Enabled Default (333): 0
libinput Tapping Button Mapping Enabled (334): 1, 0
libinput Tapping Button Mapping Default (335): 1, 0
libinput Natural Scrolling Enabled (310): 0
libinput Natural Scrolling Enabled Default (311): 0
libinput Disable While Typing Enabled (336): 1
libinput Disable While Typing Enabled Default (337): 1
libinput Scroll Methods Available (312): 1, 1, 0
libinput Scroll Method Enabled (313): 1, 0, 0
libinput Scroll Method Enabled Default (314): 1, 0, 0
libinput Accel Speed (319): 0.000000
libinput Accel Speed Default (320): 0.000000
libinput Left Handed Enabled (324): 0
libinput Left Handed Enabled Default (325): 0
libinput Send Events Modes Available (295): 1, 1
libinput Send Events Mode Enabled (296): 0, 0
libinput Send Events Mode Enabled Default (297): 0, 0
Device Node (298): "/dev/input/event7"
Device Product ID (299): 1267, 32
libinput Drag Lock Buttons (326): <no items>
libinput Horizontal Scroll Enabled (327): 1
Lenovo Thinkpad T480s (20L7CTO1WW)
The touchpad area (without the physical buttons) is 100x63mm.
I attached a recording of that event - this is a click and a drag down-right a little bit. When I do the same thing with my mouse, it moves the window.
With the touchpad I saw the "dragging icon", but the window did not move.
However, if I click (and hold it pressed) and drag with the same finger - it does work. But it is very uncomfortable to do...
Also, the click-and-drag works with mtrack, on the same device and the same DE (Plasma).
And a couple more observations.
I thought it might be "disable while typing", but changing that property doesn't help.
When I do the same thing, but use a physical button to click, I can drag things around using the touchpad.
Also, it looks like "Dragging" while pressing the touchpad with the other finger makes the content scroll instead (so I guess it registers as two finger scroll?).
Is this project even alive?
I think the entire libinput community has moved over to gitlab in the meantime. I do have the exact same issue as you do though, same Thinkpad model and everything, so I might open an report over there and link to your explanations here.
"Is this project even alive?"
yes, please see https://wayland.freedesktop.org/libinput/doc/latest/reporting-bugs.html, we're on gitlab now. You filed the bug against XWayland which is an x server implementation using Wayland as the rendering protocol (-ish) and has nothing to do with libinput. Hence no response (because it too is severely understaffed).
Paul has opened a bug for you here: https://gitlab.freedesktop.org/libinput/libinput/issues/177