Detached DOM tree entry

Regarding some old bug reports like https://bugs.jqueryui.com/ticket/10629 and https://bugs.jqueryui.com/ticket/9555.

I was playing around with jquery-ui and I found this Detached DOM tree entry without using the datepicker from jquery-ui (which by the way does not appear if you call for example $("#foo").datepicker().

I also made a small change to the code in order to fix this and here it is in case you would want to include it in some newer version.

jquery-ui-1.12-1.js

on line 7305 I commented the following line

//~ this.dpDiv = datepicker_bindHover( $( "<div id='" + this._mainDivId + "' class='ui-datepicker ui-widget ui-widget-content ui-helper-clearfix ui-corner-all'></div>" ) );

and placed the same line a bit changed, as far as "this." concerns, after line 9241

/* Append datepicker main container to body if not exist. */
if ( $( "#" + $.datepicker._mainDivId ).length === 0 ) {
	$.datepicker.dpDiv = datepicker_bindHover( $( "<div id='" + $.datepicker._mainDivId + "' class='ui-datepicker ui-widget ui-widget-content ui-helper-clearfix ui-corner-all'></div>" ) );
	$( "body" ).append( $.datepicker.dpDiv );
}