Dialog: Ensure dialogs have a z-index when calculating the max z-index. Fixex #5955 - Dialog: Closing UI dialog when z-index is not defined in any .ui-dialog class, causes NaN to be used as Z-index, throwing an error. Fixes #4652 - Dialog: Event loss in subsequent dialog calls (FF3).
Dialog: Ensure dialogs have a z-index when calculating the max z-index. Fixex #5955 - Dialog: Closing UI dialog when z-index is not defined in any .ui-dialog class, causes NaN to be used as Z-index, throwing an error. Fixes #4652 - Dialog: Event loss in subsequent dialog calls (FF3).

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