public ToolbarCommandCollection(string app, string name, CommandCollection globalCommands, string fileName) : this(app, name, globalCommands, fileName, null)
 {
 }
 public ToolbarCommandCollection(string app, string name, CommandCollection globalCommands, IEnumerable <ToolbarCommand> defaultCommands) : this(app, name, globalCommands, string.Empty, defaultCommands)
 {
 }