fixes #11638: modify DropDownButton to not assume dropDown is set upon creation of the button. 
fixes #11638: modify DropDownButton to not assume dropDown is set upon creation of the button. 

To lazy-load a dropdown menu, overwrite the default loadDropDown function to create the menu (and populate it) and attach it to this.dropDown


git-svn-id: 674a2d6b1e32e53f607eb824547723f32280967e@22770 560b804f-0ae3-0310-86f3-f6aa0a117693

redaktor/deliteful