demos: added opacity, revert and scroll demos

draggable: fixed positioning issue with relative positioned elements relative to the body during scroll 

1 files changed, 11 insertions, 1 deletions

diff --git a/ui/ui.draggable.js b/ui/ui.draggable.js
index f667c3b36..e6ccc2280 100644
--- a/ui/ui.draggable.js
+++ b/ui/ui.draggable.js
@@ -588,13 +588,23 @@ $.ui.plugin.add("draggable", "scroll", {
 
 
 
-		//This is a special case where we need to modify a offset calculated on start, since the following happened:
+		// This is a special case where we need to modify a offset calculated on start, since the following happened:
 		// 1. The position of the helper is absolute, so it's position is calculated based on the next positioned parent
 		// 2. The actual offset parent is a child of the scroll parent, and the scroll parent isn't the document, which means that
 		//    the scroll is included in the initial calculation of the offset of the parent, and never recalculated upon drag
 		if(scrolled !== false && i.cssPosition == 'absolute' && i.scrollParent[0] != document && $.ui.contains(i.scrollParent[0], i.offsetParent[0])) {
 			i.offset.parent = i._getParentOffset();
+			
 		}
+		
+		// This is another very weird special case that only happens for relative elements:
+		// 1. If the css position is relative
+		// 2. and the scroll parent is the document or similar to the offset parent
+		// we have to refresh the relative offset during the scroll so there are no jumps
+		if(scrolled !== false && i.cssPosition == 'relative' && !(i.scrollParent[0] != document && i.scrollParent[0] != i.offsetParent[0])) {
+			i.offset.relative = i._getRelativeOffset();
+		}
+		
 
 	}
 });