From 4e8310a4f3ecd1a65b635288eb3396d311ad905e Mon Sep 17 00:00:00 2001
From: "Maxim.Mossienko" <Maxim.Mossienko@jetbrains.com>
Date: Fri, 28 Apr 2017 12:42:20 +0200
Subject: [PATCH] in deactivate ask to terminate background children
 calculation to avoid edt blocking

---
 .../src/com/intellij/ide/util/treeView/AbstractTreeUi.java   | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/platform/platform-api/src/com/intellij/ide/util/treeView/AbstractTreeUi.java b/platform/platform-api/src/com/intellij/ide/util/treeView/AbstractTreeUi.java
index af488ee2128a..bd43b9a374c9 100644
--- a/platform/platform-api/src/com/intellij/ide/util/treeView/AbstractTreeUi.java
+++ b/platform/platform-api/src/com/intellij/ide/util/treeView/AbstractTreeUi.java
@@ -408,7 +408,8 @@ public class AbstractTreeUi {
     myBusyAlarm.cancelAllRequests();
 
     if (!myWasEverShown) return;
-
+    // ask for termination of background children calculation
+    if (myProgress != null && myProgress.isRunning()) myProgress.cancel();
     if (!isReady()) {
       cancelUpdate();
       myUpdateFromRootRequested = true;
@@ -918,7 +919,7 @@ public class AbstractTreeUi {
     while(true) {
       try (LockToken ignored = attemptLock()) {
         if (ignored == null) {  // async children calculation is in progress under lock
-          if (!myProgress.isCanceled()) myProgress.cancel();
+          if (myProgress != null && myProgress.isRunning()) myProgress.cancel();
           continue;
         }
         final AtomicBoolean update = new AtomicBoolean();