try to provide a cause for PCE happening in disposable indicators

e.g. daemon's

platform/core-impl/src/com/intellij/openapi/progress/util/AbstractProgressIndicatorBase.java

@@ -15,6 +15,7 @@
  */
 package com.intellij.openapi.progress.util;
 
+import com.intellij.openapi.Disposable;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.application.ModalityState;
 import com.intellij.openapi.application.TransactionGuard;
@@ -25,13 +26,16 @@ import com.intellij.openapi.progress.ProcessCanceledException;
 import com.intellij.openapi.progress.ProgressIndicator;
 import com.intellij.openapi.progress.ProgressManager;
 import com.intellij.openapi.progress.impl.CoreProgressManager;
+import com.intellij.openapi.util.Disposer;
 import com.intellij.openapi.util.UserDataHolderBase;
 import com.intellij.ui.mac.foundation.MacUtil;
+import com.intellij.util.ObjectUtils;
 import com.intellij.util.containers.ContainerUtil;
 import com.intellij.util.containers.DoubleArrayList;
 import com.intellij.util.containers.Stack;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.Set;
 
@@ -127,15 +131,23 @@ public class AbstractProgressIndicatorBase extends UserDataHolderBase implements
   @Override
   public void checkCanceled() {
     if (isCanceled() && isCancelable()) {
-      throw new ProcessCanceledException();
+      throw new ProcessCanceledException(getDisposeTrace());
     }
     if (CoreProgressManager.runCheckCanceledHooks(this)) {
       if (isCanceled() && isCancelable()) {
-        throw new ProcessCanceledException();
+        throw new ProcessCanceledException(getDisposeTrace());
       }
     }
   }
 
+  @Nullable
+  private Throwable getDisposeTrace() {
+    if (this instanceof Disposable) {
+      return ObjectUtils.tryCast(Disposer.getTree().getDisposalInfo((Disposable)this), Throwable.class);
+    }
+    return null;
+  }
+
   @Override
   public void setText(final String text) {
     myText = text;

platform/util/src/com/intellij/openapi/progress/ProcessCanceledException.java

@@ -16,12 +16,12 @@
 package com.intellij.openapi.progress;
 
 import com.intellij.openapi.diagnostic.ControlFlowException;
-import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public class ProcessCanceledException extends RuntimeException implements ControlFlowException {
   public ProcessCanceledException() { }
 
-  public ProcessCanceledException(@NotNull Throwable cause) {
+  public ProcessCanceledException(@Nullable Throwable cause) {
     super(cause);
     if (cause instanceof ProcessCanceledException) {
       throw new IllegalArgumentException("Must not self-wrap ProcessCanceledException: " + cause);