Refresh jquery ui dialog position -

I am using a jquery dialog The content of this dialog is dynamic, so when the dialog is open then the height change She goes.

  $ ("# a_div"). Dialog ({width: 400});   
 Dialog is initially displayed in the center of the page.  
 Thanks   
  
  
 Div class = "post-text" itemprop = "text"> 
 You will need to reset the status again:  
  $ ("# a_div"). Dialog ({status: {'Mary': 'center', 'on': 'center'}});   
 When set up the dialog is set once, but can be changed later (or reset to the same value, forcing jQuery to recalculate).  
 See this demo: