OpenSong

When clicking "Move Up" or "Move Dn" more times than there are items above
or below, an array index out of bounds exception is thrown with the
following log:

OutOfBoundsException:

Stacktrace:
RaiseOutOfBoundsException
_ZN14RuntimeListbox7GetTextE15getTextSelectorll
RuntimeGetRow
Listbox.List%s%o<Listbox>i4
MainWindow.MainWindow.btn_set_move_down_Action%%o<MainWindow.MainWindow>
SButton.Event_MouseUp%%o<SButton>i4i4
_ZN13RuntimeCanvas13HandleMouseUpEii
_ZN16PumpedEventQueue11FilterEventEP11EventRecord
_Z36PumpedEventQueueInternalHandleEventsv
_Z28PumpedEventQueueHandleEventsv
_Z17UpdateMouseCursorv
_Z17IsAppShuttingDownv
_Z33CallFunctionWithExceptionHandlingPFvvE
_Z8mainloopv
RuntimeRun
REALbasic._RuntimeRun
_Main
% main
_start