When you add an html fragment containing a Dojo Widget to a WebPage, Dojo does not interpret this html fragment. So this new widget is not added to the Dojo manager and it does not work. This kind of dom opration often happens in Ajax application using Dojo so you can force dojo to add this widget to the manager in order to make it work with this 2 lines :

  djConfig.searchIds = ['widgetIdToInterpret']; 
  dojo.hostenv.makeWidgets();

searchIds is a table containing widget to interpret by Dojo manager and the dojo.hostenv.makeWidgets runs the dojo interpretor to make the new widget