Addressed GH-119 - for heap dumps comparison the visual bar for diff of instances is now visible by default, initial sorting now by instances

Author: jisedlac

visualvm/heapviewer/src/org/graalvm/visualvm/heapviewer/java/impl/JavaDiffObjectsView.java

@@ -138,8 +138,10 @@ public JavaDiffObjectsView(HeapContext context1, File file2, final boolean compa
 
         final Heap heap = context1.getFragment().getHeap();
 
-        final TreeTableViewColumn countC = new TreeTableViewColumn.Count(heap);
-        final TreeTableViewColumn sizeC = new TreeTableViewColumn.OwnSize(heap, true, true);
+        final TreeTableViewColumn countC = new TreeTableViewColumn.Count(heap, true, true) {
+            public int getPreferredWidth() { return ((HideableBarRenderer)getRenderer()).getOptimalWidth(); }
+        };
+        final TreeTableViewColumn sizeC = new TreeTableViewColumn.OwnSize(heap, true, false);
         final TreeTableViewColumn retainedC = compareRetained ? new TreeTableViewColumn.RetainedSize(heap) : null;
 
         TreeTableViewColumn[] columns = compareRetained ?