Hello,
I own an Inspiron 5558. I have this weird issue with a touchpad. Normally, the single tap is equal to a left mouse button single click. However, randomly from time to time, it switches to a mode in which a single tap holds the left mouse button and the only way to let go is to single click a physical touchpad buton. I have installed the latest touchpad drivers. I have also reinstalled Windows but it didn't help. I have noticed that if I log out and log in again, the touchpad works normally again. Also, If I switch user the issue does not exist on another account, but when I come back to my normal Windows account, it behaves weirdly again. Please help, it is really annoying when you relay in a touchpad.