Ticket #4765: jQuery.ui.sortable_tr_placeholder_fix.patch

Index: ui/jquery.ui.sortable.js
===================================================================
--- ui/jquery.ui.sortable.js	(revision 3571)
+++ ui/jquery.ui.sortable.js	(working copy)
@@ -608,8 +608,19 @@
 			o.placeholder = {
 				element: function() {
 
-					var el = $(document.createElement(self.currentItem[0].nodeName))
-						.addClass(className || self.currentItem[0].className+" ui-sortable-placeholder")
+					var nodeType = self.currentItem[0].nodeName;
+					var el = $(document.createElement(nodeType));
+
+					// For tr elements create a child td element and apply styles there, as empty tr tags aren't rendered in webkit browsers
+					if (nodeType.toLowerCase() != "tr") {
+						var styledNode = el;
+					} else {
+						var styledNode = $(document.createElement('td'))
+							.attr('colspan', self.currentItem[0].children.length);
+						el.append(styledNode);
+					}
+
+					styledNode.addClass(className || self.currentItem[0].className+" ui-sortable-placeholder")
 						.removeClass("ui-sortable-helper")[0];
 
 					if(!className)
@@ -623,9 +634,17 @@
 					// 2. The option 'forcePlaceholderSize can be enabled to force it even if a class name is specified
 					if(className && !o.forcePlaceholderSize) return;
 
+					// If the placeholder is a tr element, apply sizes to its child td tag as some browsers ignore them on the tr element.
+						// Also skip setting the width as it causes column widths in firefox to jump wider and then back to normal.
+					var skipWidth = false;
+					if (p.get(0).nodeName.toLowerCase() == 'tr') {
+						p = p.children(':first');
+						skipWidth = true;
+					}
+
 					//If the element doesn't have a actual height by itself (without styles coming from a stylesheet), it receives the inline height from the dragged item
 					if(!p.height()) { p.height(self.currentItem.innerHeight() - parseInt(self.currentItem.css('paddingTop')||0, 10) - parseInt(self.currentItem.css('paddingBottom')||0, 10)); };
-					if(!p.width()) { p.width(self.currentItem.innerWidth() - parseInt(self.currentItem.css('paddingLeft')||0, 10) - parseInt(self.currentItem.css('paddingRight')||0, 10)); };
+					if(!skipWidth && !p.width()) { p.width(self.currentItem.innerWidth() - parseInt(self.currentItem.css('paddingLeft')||0, 10) - parseInt(self.currentItem.css('paddingRight')||0, 10)); };
 				}
 			};
 		}