After I had upgraded my system from 19.04 to Kubuntu 19.10 my touchpad got mad.
It looks like it interpreted whole touchpad area as a right bar area and couldn't decide if I'm moving a pointer or scrolling. So I disabled vertical scrolling except for two-fingers method.

Then it mistakenly interpreted some touches as middle button clicks, bcs top-right zone was incorrect too. So I've disabled middle button events for it.

Now I'm experiencing a problem with click detection - it seems I have to press harder than usual to get my actions detected in some apps (Firefox). And it looks like it's already a max sensitivity.

Resetting to defaults doesn't help.

Operating System: Kubuntu 19.10
KDE Plasma Version: 5.16.5
KDE Frameworks Version: 5.62.0
Qt Version: 5.12.4
Kernel Version: 5.3.0-18-generic
OS Type: 64-bit
Processors: 4 × Intel® Core™ i7-3520M CPU @ 2.90GHz
Memory: 7,6 GiB of RAM

Laptop - Lenovo G780

$ xinput list-props 17                            
Device 'ETPS/2 Elantech Touchpad':
        Device Enabled (169):   1
        Coordinate Transformation Matrix (171): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
        Device Accel Profile (303):     1
        Device Accel Constant Deceleration (304):       2.500000
        Device Accel Adaptive Deceleration (305):       1.000000
        Device Accel Velocity Scaling (306):    12.500000
        Synaptics Edges (311):  58, 1412, 34, 596
        Synaptics Finger (312): 1, 1, 0
        Synaptics Tap Time (313):       250
        Synaptics Tap Move (314):       70
        Synaptics Tap Durations (315):  180, 180, 100
        Synaptics ClickPad (316):       0
        Synaptics Middle Button Timeout (317):  75
        Synaptics Two-Finger Pressure (318):    282
        Synaptics Two-Finger Width (319):       7
        Synaptics Scrolling Distance (320):     31, 31
        Synaptics Edge Scrolling (321): 0, 0, 0
        Synaptics Two-Finger Scrolling (322):   1, 0
        Synaptics Move Speed (323):     1.000000, 1.750000, 0.125078, 0.000000
        Synaptics Off (324):    2
        Synaptics Locked Drags (325):   0
        Synaptics Locked Drags Timeout (326):   5000
        Synaptics Tap Action (327):     0, 0, 0, 0, 1, 3, 0
        Synaptics Click Action (328):   1, 1, 0
        Synaptics Circular Scrolling (329):     0
        Synaptics Circular Scrolling Distance (330):    0.100007
        Synaptics Circular Scrolling Trigger (331):     0
        Synaptics Circular Pad (332):   0
        Synaptics Palm Detection (333): 0
        Synaptics Palm Dimensions (334):        10, 200
        Synaptics Coasting Speed (335): 20.000000, 50.000000
        Synaptics Pressure Motion (336):        30, 160
        Synaptics Pressure Motion Factor (337): 1.000000, 1.000000
        Synaptics Resolution Detect (338):      1
        Synaptics Grab Event Device (339):      0
        Synaptics Gestures (340):       1
        Synaptics Capabilities (341):   1, 0, 1, 1, 1, 1, 1
        Synaptics Pad Resolution (342): 31, 31
        Synaptics Area (343):   0, 0, 0, 0
        Synaptics Noise Cancellation (344):     7, 7
        Device Product ID (296):        2, 14
        Device Node (295):      "/dev/input/event8"


[quote]
$ cat /usr/share/X11/xorg.conf.d/70-synaptics.conf
# Example xorg.conf.d snippet that assigns the touchpad driver
# to all touchpads. See xorg.conf.d(5) for more information on
# InputClass.
# DO NOT EDIT THIS FILE, your distribution will likely overwrite
# it when updating. Copy (and rename) this file into
# /etc/X11/xorg.conf.d first.
# Additional options may be added in the form of
#   Option "OptionName" "value"
#
Section "InputClass"
        Identifier "touchpad catchall"
        Driver "synaptics"
        MatchIsTouchpad "on"
# This option is recommend on all Linux systems using evdev, but cannot be
# enabled by default. See the following link for details:
# http://who-t.blogspot.com/2010/11/how-to-ignore-configuration-errors.html
      MatchDevicePath "/dev/input/event*"
EndSection

Section "InputClass"
        Identifier "touchpad ignore duplicates"
        MatchIsTouchpad "on"
        MatchOS "Linux"
        MatchDevicePath "/dev/input/mouse*"
        Option "Ignore" "on"
EndSection

# This option enables the bottom right corner to be a right button on clickpads
# and the right and middle top areas to be right / middle buttons on clickpads
# with a top button area.
# This option is only interpreted by clickpads.
Section "InputClass"
        Identifier "Default clickpad buttons"
        MatchDriver "synaptics"
        Option "SoftButtonAreas" "50% 0 82% 0 0 0 0 0"
        Option "SecondarySoftButtonAreas" "58% 0 0 15% 42% 58% 0 15%"
EndSection

# This option disables software buttons on Apple touchpads.
# This option is only interpreted by clickpads.
Section "InputClass"
        Identifier "Disable clickpad buttons on Apple touchpads"
        MatchProduct "Apple|bcm5974"
        MatchDriver "synaptics"
        Option "SoftButtonAreas" "0 0 0 0 0 0 0 0"
EndSection
[/quote]