inspection toolwindow: first add view the update view (npes in suppressable nodes)

platform/lang-impl/src/com/intellij/codeInspection/actions/ViewOfflineResultsAction.java

@@ -225,9 +225,8 @@ public class ViewOfflineResultsAction extends AnAction {
     final InspectionResultsView view = new InspectionResultsView(context,
                                                                  new OfflineInspectionRVContentProvider(resMap, project));
     ((RefManagerImpl)context.getRefManager()).startOfflineView();
-    view.update();
-    TreeUtil.selectFirstNode(view.getTree());
     context.addView(view, title, true);
+    view.update();
     return view;
   }
 }

platform/lang-impl/src/com/intellij/codeInspection/ex/GlobalInspectionContextImpl.java

@@ -369,8 +369,8 @@ public class GlobalInspectionContextImpl extends GlobalInspectionContextBase imp
           }
         }
         else if (view != null) {
-          view.update();
           addView(view);
+          view.update();
         }
         if (myView != null) {
           myView.setUpdating(false);

platform/lang-impl/src/com/intellij/codeInspection/ui/InspectionTreeNodeReuser.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2000-2016 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.codeInspection.ui;
+
+import com.intellij.codeInspection.CommonProblemDescriptor;
+import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.util.ui.tree.TreeUtil;
+import gnu.trove.THashMap;
+
+import java.util.Map;
+import java.util.function.Supplier;
+
+/**
+ * @author dima
+ */
+//guarded by single tree rebuild thread
+public class InspectionTreeNodeReuser {
+  private final static Logger LOG = Logger.getInstance(InspectionTreeNodeReuser.class);
+  private final Map<CommonProblemDescriptor, ProblemDescriptionNode> myReusedNodes = new THashMap<>();
+
+  public InspectionTreeNodeReuser(InspectionTree tree) {
+    TreeUtil.traverse(tree.getRoot(), n -> {
+      if (n instanceof ProblemDescriptionNode) {
+        CommonProblemDescriptor descriptor = ((ProblemDescriptionNode)n).getDescriptor();
+        if (descriptor != null) {
+          myReusedNodes.put(descriptor, (ProblemDescriptionNode)n);
+        }
+      }
+      return true;
+    });
+  }
+
+  public ProblemDescriptionNode getOrCreate(CommonProblemDescriptor descriptor, Supplier<ProblemDescriptionNode> produces) {
+    ProblemDescriptionNode node = myReusedNodes.get(descriptor);
+    if (node != null) {
+      return node;
+    }
+    return produces.get();
+  }
+}

platform/lang-impl/src/com/intellij/codeInspection/ui/SuppressableInspectionTreeNode.java

@@ -36,11 +36,12 @@ import java.util.Set;
  */
 public abstract class SuppressableInspectionTreeNode extends CachedInspectionTreeNode implements RefElementAndDescriptorAware {
   private final static Logger LOG = Logger.getInstance(SuppressableInspectionTreeNode.class);
+  @NotNull
   private final InspectionResultsView myView;
   private volatile Set<SuppressIntentionAction> myAvailableSuppressActions;
   protected final InspectionToolPresentation myPresentation;
 
-  protected SuppressableInspectionTreeNode(Object userObject, InspectionToolPresentation presentation) {
+  protected SuppressableInspectionTreeNode(Object userObject, @NotNull InspectionToolPresentation presentation) {
     super(userObject);
     myView = presentation.getContext().getView();
     myPresentation = presentation;