LPS-49362 Listener created when window is openned

Hi Nate, 

I think that the change you suggested here does not apply in our case. `Liferay.Util.getPortletId()` works with this kind of ids: "p_p_id_125_" (portlet id). But what we have here is the dialog id, which is "_125_selectGroup", so I think we still need this regular expresion. I din't find any other method for this situation. Please let me know if I am wrong. 

You were right about the comments you made in site.jsp and I have corrected them. I am sending you a new pull request...