Datepicker: Fixed position problem when input is in a fixed element. Fixes #5626 - DatePicker doesn't work inside fixed div.

(cherry picked from commit 147ec7b)

Author: luisdalmolin

ui/jquery.ui.datepicker.js

@@ -765,8 +765,8 @@ $.extend(Datepicker.prototype, {
 		var dpHeight = inst.dpDiv.outerHeight();
 		var inputWidth = inst.input ? inst.input.outerWidth() : 0;
 		var inputHeight = inst.input ? inst.input.outerHeight() : 0;
-		var viewWidth = document.documentElement.clientWidth + $(document).scrollLeft();
-		var viewHeight = document.documentElement.clientHeight + $(document).scrollTop();
+		var viewWidth = document.documentElement.clientWidth + (isFixed ? 0 : $(document).scrollLeft());
+		var viewHeight = document.documentElement.clientHeight + (isFixed ? 0 : $(document).scrollTop());
 
 		offset.left -= (this._get(inst, 'isRTL') ? (dpWidth - inputWidth) : 0);
 		offset.left -= (isFixed && offset.left == inst.input.offset().left) ? $(document).scrollLeft() : 0;