My Solus 4 Plasma has 3 problems with Touchpad option in Setting:
- Resume after sleep have 'Tapping' and 'Two-finger tap' option are greyed-out, but after few minutes these option comeback to normal.
- Option 'Middle-click' doesn't display well in 2 different display stages, one directly from Setting open page, one throught 'Input Devices' option
- 'Right-Click' option alway grey-out

