macbook air flickering on firefox or microsoft word

[Harry Eub]

I have a 2014 early macbook air with liquid damage but got repaired. Now everything is working very well except the firefox and microsoft word at 1440x900 resolution. It gets colour flickering bar on the top or the side as the picture I attached. Safari won't have this problem. Google chrome used to have this problem but it is fixed after I turned off "hardware acceleration". I have tried to turn off "hardware acceleration" on firefox or disable all of the add-on, but no lucky. when the resolution down to 1280x800, everything perfect on firefox and microsoft word. Anyone have any idea and solution for this? Many thanks for your help ahead!