I have a Raspberry Pi set up as a web kiosk that displays a web app that I wrote for parents to check their children in and out of a preschool. The browser is chromium in kiosk mode. The web app is written in php and runs in apache on an OpenSuse server. A mariadb database is used to store the pins and list of children.
The users interact with it by pressing onscreen buttons to enter their 4-digit pin code. They are then presented with a button for each of their children that they can click to log in or out.
Frequently when a user presses a button on screen, instead of the click being registered, they get a little file icon where they pressed that disappears as soon as they lift their finger. This icons appearance means the button wasn't pressed and they have to press it again. This happens with such frequency that to enter the 4 digit pin frequently requires 6-12 taps.
I think this is happening because their presses aren't straight clicks. There is some small amount of "roll" in their finger as they press and the pi is judging it to be a drag event.
How can I prevent this from happening?