failed in _destroyOverlay when I destroy a modal dialog thau was never opened.

I create a modal dialog.

If I show this dialog the destroy works fine.

If I call the destroy dialog function without showing at least one time this dialog, the _destroyOverlay function failed beacause overlay is null.

I solve the problem by testing the overlayInstances value.

if ( $.ui.dialog.overlayInstances > 0 ) {

$.ui.dialog.overlayInstances--;

if ( !$.ui.dialog.overlayInstances ) {

this._off( this.document, "focusin" );

}

this.overlay.remove();

}