Running Powerpoint on a Mac with the Magic Mouse causes an irritating problem where every so often, for no apparent reason, the scrolling goes crazy - suddenly skipping several slides forward or backwards. Usually while in the middle of doing some sort of fine-tuning of a slide with a rapidly approaching deadline.

After some googling, I found that disabling "scroll direction natural" in System Preferences seems to fix it. I don't know why, but it does.

However, its an annoying thing to have to do on a regular basis. So I made an Applescript to quickly deal with it;

tell application "System Preferences"
activate
set current pane to pane "com.apple.preference.trackpad"
end tell

tell application "System Events"
    tell process "System Preferences"
        click radio button "Scroll & Zoom" of tab group 1 of window "Trackpad"

        set theCheckbox to checkbox 1 of tab group 1 of window "Trackpad"

        tell theCheckbox
            set checkBoxStatus to value of theCheckbox as boolean
            if checkBoxStatus is false then click theCheckbox
        end tell

    end tell
end tell

tell application "System Preferences"
    quit
end tell

I use Keyboard Maestro to trigger the command, and have a corresponding one to turn it back on again (just change the line "if checkBoxStatus is false then click theCheckbox" to "if checkBoxStatus is true then click theCheckbox".) You could probably set it up in Automator as an OSX Service to be available in Powerpoint, and then assign a shortcut key to activate/deactivate it.

I've saved a gist over at Github - feel free to send any improvements etc. over there, or add a comment here if you have any suggestions.