I was using atom-beta fine yesterday. Today I am seeing tearing on top of the editor window, which is a horizontal white band about two lines high, which a step profile.
Environment is Ubuntu 16.04 with LightDM
Atom : 1.28.0-beta2
Chrome : 61.0.3163.100
Node : 8.9.3
I have a screenshot if this is helpful.
I am also sure this will go away if I log in again!