improve dropdown open up/down mode. fixes #589

select2.js

@@ -935,21 +935,21 @@ the specific language governing permissions and limitations under the Apache Lic
                 height = this.container.outerHeight(false),
                 width = this.container.outerWidth(false),
                 dropHeight = this.dropdown.outerHeight(false),
-	        viewPortRight = $(window).scrollLeft() + document.documentElement.clientWidth,
-                viewportBottom = $(window).scrollTop() + document.documentElement.clientHeight,
+	            viewPortRight = $(window).scrollLeft() + $(window).width(),
+                viewportBottom = $(window).scrollTop() + $(window).height(),
                 dropTop = offset.top + height,
                 dropLeft = offset.left,
                 enoughRoomBelow = dropTop + dropHeight <= viewportBottom,
                 enoughRoomAbove = (offset.top - dropHeight) >= this.body().scrollTop(),
-	        dropWidth = this.dropdown.outerWidth(false),
-	        enoughRoomOnRight = dropLeft + dropWidth <= viewPortRight,
+	            dropWidth = this.dropdown.outerWidth(false),
+	            enoughRoomOnRight = dropLeft + dropWidth <= viewPortRight,
                 aboveNow = this.dropdown.hasClass("select2-drop-above"),
                 bodyOffset,
                 above,
                 css;
 
-            // console.log("below/ droptop:", dropTop, "dropHeight", dropHeight, "sum", (dropTop+dropHeight)+" viewport bottom", viewportBottom, "enough?", enoughRoomBelow);
-            // console.log("above/ offset.top", offset.top, "dropHeight", dropHeight, "top", (offset.top-dropHeight), "scrollTop", this.body().scrollTop(), "enough?", enoughRoomAbove);
+            //console.log("below/ droptop:", dropTop, "dropHeight", dropHeight, "sum", (dropTop+dropHeight)+" viewport bottom", viewportBottom, "enough?", enoughRoomBelow);
+            //console.log("above/ offset.top", offset.top, "dropHeight", dropHeight, "top", (offset.top-dropHeight), "scrollTop", this.body().scrollTop(), "enough?", enoughRoomAbove);
 
             // fix positioning when body has an offset and is not position: static
 
@@ -969,9 +969,9 @@ the specific language governing permissions and limitations under the Apache Lic
                 if (!enoughRoomBelow && enoughRoomAbove) above = true;
             }
 
-	    if (!enoughRoomOnRight) {
-		   dropLeft = offset.left + width - dropWidth;
-	    }
+            if (!enoughRoomOnRight) {
+               dropLeft = offset.left + width - dropWidth;
+            }
 
             if (above) {
                 dropTop = offset.top - dropHeight;