GDM Login/Greeter User List Scrolling

Hi Community,

On RHEL 7.6 in the GDM greeter/login screen I am experiencing strange (to me) scrolling behavior in the user list.

When I move the mouse pointer into the bottom half of the list panel, it automatically starts scrolling down. When I move the mouse pointer into the top half of the list panel, it then starts scrolling back up. Because it starts scrolling as the pointer moves to the desired user, the user slips past before it can be clicked on.

How is scrolling happening when no buttons or scroll-wheel are being pressed?

Thanks,
Rob