to showOpenPanel for message given allowedTypes:allowedTypes : missing value, buttonName:buttonName : missing value, directory:directory : missing value, showHidden:showHidden : false, traversePackages:traversePackages : false, accessory:accessory : missing value, returnPosix:returnPosix : true, chooseFiles:chooseFiles : true, chooseFolders:chooseFolders : false, allowMultiple:allowMultiple : true, showAccessory:showAccessory : false