tell application "System Events"
    repeat with theProcess in processes
        if not background only of theProcess then
            tell theProcess
                set processName to name
                set theWindows to windows
            end tell
            set windowsCount to count of theWindows

            if processName is "zoom.us" then
                repeat with theWindow in theWindows
      tell theWindow
   set theSize to size
                        set windowName to name
      end tell
                    if windowName is "annotation panel" then
                        if item 1 of theSize is 776 then
                            tell theWindow to tell button 5 to click
                            key code 49
                        else
                            tell theWindow to tell button 4 to click
                            key code 49
                        end if
      end if
                end repeat
            end if
        end if
    end repeat
    end tell