I can reproduce this error. set theList to ( processes whose frontmost is true ) log ( get id of item 1 of theList ) and set frontApp to first process whose frontmost is true log ( get id of frontApp) gives different results then repeat with theProcess in processes whose frontmost is true set frontApp to theProcess end repeat log ( get id of frontApp ) when multiple applications (i.e. VSCode and another electron app) are both running.