From 2ae28c7629efce323b00fe9aba61339d832f5cd4 Mon Sep 17 00:00:00 2001
From: Alexey Kudravtsev <cdr@intellij.com>
Date: Wed, 15 Mar 2017 19:17:05 +0300
Subject: [PATCH] disable access to usage view tree outside EDT to fix
 IDEA-168857 Find usages preview throws exception: java.lang.Throwable

---
 .../usageView/src/com/intellij/usages/impl/UsageViewImpl.java | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/platform/usageView/src/com/intellij/usages/impl/UsageViewImpl.java b/platform/usageView/src/com/intellij/usages/impl/UsageViewImpl.java
index 3182b17fc24a..b1f237ee9d83 100644
--- a/platform/usageView/src/com/intellij/usages/impl/UsageViewImpl.java
+++ b/platform/usageView/src/com/intellij/usages/impl/UsageViewImpl.java
@@ -1700,7 +1700,9 @@ public class UsageViewImpl implements UsageView {
         sink.put(PlatformDataKeys.COPY_PROVIDER, myCopyProvider);
       }
       else {
-        Node node = getSelectedNode();
+        // can arrive here outside EDT from usage view preview.
+        // ignore all these fancy actions in this case.
+        Node node = ApplicationManager.getApplication().isDispatchThread() ? getSelectedNode() : null;
         if (node != null) {
           Object userObject = node.getUserObject();
           if (userObject instanceof TypeSafeDataProvider) {