copy array for undo to be implementation independent
copy array for undo to be implementation independent
WoLpH/skim,ycaihua/skim-app,ycaihua/skim-app,WoLpH/skim,WoLpH/skim,ycaihua/skim-app,ycaihua/skim-app,WoLpH/skim,ycaihua/skim-app,WoLpH/skim