Fix italic left over by the Show node.

As we set italic font to Show item updating the item with new element
left behind it's font.
Now destroy the Show item and create items from it's position onwards.
(No impact on performance - previous performance data matches with the
fix)

Fixes #1032

Author: raghucssit

bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TableViewer.java

@@ -478,15 +478,13 @@ void handleExpandableNodeClicked(Widget w) {
 			Object[] nextChildren = applyItemsLimit(data, sortedChildren);
 
 			if (nextChildren.length > 0) {
-				// update the expandable node with first item.
-				doUpdateItem(item, nextChildren[0], true);
-				// create remaining elements
-				if (nextChildren.length > 1) {
-					// current index is updated so start creating from next index.
-					int index = doIndexOf(item) + 1;
-					for (int i = 1; i < nextChildren.length; i++) {
-						createItem(nextChildren[i], index++);
-					}
+				disassociate(item);
+				int index = doIndexOf(item);
+				// will also call item.dispose()
+				doRemove(new int[] { index });
+
+				for (int i = 0; i < nextChildren.length; i++) {
+					createItem(nextChildren[i], index++);
 				}
 				// If we've expanded but still have not reached the limit
 				// select new expandable node, so user can click through

bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java

@@ -1159,15 +1159,13 @@ void handleExpandableNodeClicked(Widget w) {
 				parent = getControl();
 			}
 
-			// update widget
-			updateItem(item, children[0]);
-			updatePlus(item, children[0]);
-
-			if (children.length > 1) {
-				// create children on parent
-				for (int i = 1; i < children.length; i++) {
-					createTreeItem(parent, children[i], -1);
-				}
+			// destroy widget
+			disassociate(item);
+			item.dispose();
+
+			// create children on parent
+			for (Object element : children) {
+				createTreeItem(parent, element, -1);
 			}
 
 			// If we've expanded but still have not reached the limit