code: public void setContent(final WComponent content) {
  		WindowModel model = getOrCreateComponentModel();
  
  		// If the previous content had been wrapped, then remove it from the wrapping WApplication.
  		if (model.wrappedContent != null && model.wrappedContent != model.content) {
  			model.wrappedContent.removeAll();
  		}
  
  		model.content = content;
  
  		// Wrap content in a WApplication
  		if (content instanceof WApplication) {
  			model.wrappedContent = (WApplication) content;
  		} else {
  			model.wrappedContent = new WApplication();
  			model.wrappedContent.add(content);
  		}
  
  		// There should only be one content.
  		holder.removeAll();
  		holder.add(model.wrappedContent);
  	}
docs: Set the WComponent that will handle the content for this pop up window.
  
  @param content the window content.