Draggable: Fix double offset bug when scrolling. Fixes #6817 - Draggable: auto scroll goes double distance when dragging

1 files changed, 17 insertions, 4 deletions

diff --git a/ui/jquery.ui.draggable.js b/ui/jquery.ui.draggable.js
index 5762d3171..a75f9e9f3 100644
--- a/ui/jquery.ui.draggable.js
+++ b/ui/jquery.ui.draggable.js
@@ -135,6 +135,9 @@ $.widget("ui.draggable", $.ui.mouse, {
 			left: this.offset.left - this.margins.left
 		};
 
+		//Reset scroll cache
+		this.offset.scroll = false;
+
 		$.extend(this.offset, {
 			click: { //Where the click happened, relative to the element
 				left: event.pageX - this.offset.left,
@@ -433,18 +436,23 @@ $.widget("ui.draggable", $.ui.mouse, {
 		var mod = d === "absolute" ? 1 : -1,
 			scroll = this.cssPosition === "absolute" && !(this.scrollParent[0] !== document && $.contains(this.scrollParent[0], this.offsetParent[0])) ? this.offsetParent : this.scrollParent, scrollIsRootNode = (/(html|body)/i).test(scroll[0].tagName);
 
+		//Cache the scroll
+		if (!this.offset.scroll) {
+			this.offset.scroll = {top : scroll.scrollTop(), left : scroll.scrollLeft()};
+		}
+
 		return {
 			top: (
 				pos.top	+																// The absolute mouse position
 				this.offset.relative.top * mod +										// Only for relative positioned nodes: Relative offset from element to offset parent
 				this.offset.parent.top * mod -										// The offsetParent's offset without borders (offset + border)
-				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : scroll.scrollTop() ) ) * mod)
+				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : this.offset.scroll.top ) ) * mod)
 			),
 			left: (
 				pos.left +																// The absolute mouse position
 				this.offset.relative.left * mod +										// Only for relative positioned nodes: Relative offset from element to offset parent
 				this.offset.parent.left * mod	-										// The offsetParent's offset without borders (offset + border)
-				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollLeft() : scrollIsRootNode ? 0 : scroll.scrollLeft() ) * mod)
+				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollLeft() : scrollIsRootNode ? 0 : this.offset.scroll.left ) * mod)
 			)
 		};
 
@@ -459,6 +467,11 @@ $.widget("ui.draggable", $.ui.mouse, {
 			pageX = event.pageX,
 			pageY = event.pageY;
 
+		//Cache the scroll
+		if (!this.offset.scroll) {
+			this.offset.scroll = {top : scroll.scrollTop(), left : scroll.scrollLeft()};
+		}
+
 		/*
 		 * - Position constraining -
 		 * Constrain the position to a mix of grid, containment.
@@ -508,14 +521,14 @@ $.widget("ui.draggable", $.ui.mouse, {
 				this.offset.click.top	-												// Click offset (relative to the element)
 				this.offset.relative.top -												// Only for relative positioned nodes: Relative offset from element to offset parent
 				this.offset.parent.top +												// The offsetParent's offset without borders (offset + border)
-				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : scroll.scrollTop() ) ))
+				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : this.offset.scroll.top ) ))
 			),
 			left: (
 				pageX -																	// The absolute mouse position
 				this.offset.click.left -												// Click offset (relative to the element)
 				this.offset.relative.left -												// Only for relative positioned nodes: Relative offset from element to offset parent
 				this.offset.parent.left +												// The offsetParent's offset without borders (offset + border)
-				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollLeft() : scrollIsRootNode ? 0 : scroll.scrollLeft() ))
+				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollLeft() : scrollIsRootNode ? 0 : this.offset.scroll.left ))
 			)
 		};