code: function( position ) {
  		var previous = this.parent._header.show;
  		if( this.parent._docker && this.parent._docker.docked )
  			throw new Error( 'Can\'t change header position in docked stack' );
  		if( previous && !this.parent._side )
  			previous = 'top';
  		if( position !== undefined && this.parent._header.show != position ) {
  			this.parent._header.show = position;
              this.parent.config.header ? this.parent.config.header.show = position : this.parent.config.header = { show:position };
  			this.parent._setupHeaderPosition();
  		}
  		return previous;
  	}
docs: Programmatically operate with header position.
  
  @param {string} position one of ('top','left','right','bottom') to set or empty to get it.
  
  @returns {string} previous header position