I installed Ubuntu 19.04 today. The touchpad doesn't seem to be working properly. I have natural scrolling turned on and side scroll disabled. For some reason, the sides of touchpad doesn't work. If I start moving the cursor from sides (left or right) which is the scroll area , the cursor doesn't move at all. I can start from middle of touchpad and go to the very sides and it does move but starting from side does nothing. The laptop model is HP Probook 440 G4 if that helps.
To anyone having same problem in the future, it started working for me. I don't exactly know how it worked. I ran
synclient
command on ubuntu, after which I noticed it working. You'll probably get it correct if you mess around that command or change some properties( I didn't need to).