Dialog: Only create the button pane once and store a reference to it. Fixes #8343 - _createButtons removes all elements with .ui-dialog-buttonpane class.
Dialog: Only create the button pane once and store a reference to it. Fixes #8343 - _createButtons removes all elements with .ui-dialog-buttonpane class.

GrayYoung/jQuery.UI.Extension,GrayYoung/jQuery.UI.Extension