As synaptics is no longer available for controlling touchpad, we have to use xinput instead. First, use command : xinput list to display all input devices and find out touchpad’s number. In my system the result is: ⎡ Virtual core pointer id=2 [master pointer (3)] ⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)] […]
search result talks about an “input method selector” in preference menu which was not found on my system. solution: sudo dnf install imsettings-lxde then you can find “input method selector” in preference menu.