diff --git a/java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/ModuleEditor.java b/java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/ModuleEditor.java
index d2217e96cea4..d1c7228d7f7f 100644
--- a/java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/ModuleEditor.java
+++ b/java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/ModuleEditor.java
@@ -45,6 +45,7 @@ import javax.swing.*;
 import javax.swing.event.ChangeEvent;
 import java.awt.*;
 import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 import java.util.*;
@@ -394,6 +395,9 @@ public abstract class ModuleEditor implements Place.Navigator, Disposable {
         }
         return result;
       }
+      catch (InvocationTargetException e) {
+        throw e.getCause();
+      }
       finally {
         if (needUpdate) {
           updateOrderEntriesInEditors();
@@ -433,6 +437,9 @@ public abstract class ModuleEditor implements Place.Navigator, Disposable {
         }
         return result;
       }
+      catch (InvocationTargetException e) {
+        throw e.getCause();
+      }
       finally {
         if (needUpdate) {
           updateOrderEntriesInEditors();
@@ -450,12 +457,17 @@ public abstract class ModuleEditor implements Place.Navigator, Disposable {
     }
 
     public Object invoke(Object object, Method method, Object[] params) throws Throwable {
-      final Object result = method.invoke(myDelegateLibrary, unwrapParams(params));
-      if (result instanceof Library.ModifiableModel) {
-        return Proxy.newProxyInstance(getClass().getClassLoader(), new Class[]{Library.ModifiableModel.class},
-                                      new LibraryModifiableModelInvocationHandler((Library.ModifiableModel)result));
+      try {
+        final Object result = method.invoke(myDelegateLibrary, unwrapParams(params));
+        if (result instanceof Library.ModifiableModel) {
+          return Proxy.newProxyInstance(getClass().getClassLoader(), new Class[]{Library.ModifiableModel.class},
+                                        new LibraryModifiableModelInvocationHandler((Library.ModifiableModel)result));
+        }
+        return result;
+      }
+      catch (InvocationTargetException e) {
+        throw e.getCause();
       }
-      return result;
     }
 
     public Object getDelegate() {
@@ -475,6 +487,9 @@ public abstract class ModuleEditor implements Place.Navigator, Disposable {
       try {
         return method.invoke(myDelegateModel, unwrapParams(params));
       }
+      catch (InvocationTargetException e) {
+        throw e.getCause();
+      }
       finally {
         if (needUpdate) {
           updateOrderEntriesInEditors();
@@ -510,6 +525,9 @@ public abstract class ModuleEditor implements Place.Navigator, Disposable {
         }
         return result;
       }
+      catch (InvocationTargetException e) {
+        throw e.getCause();
+      }
       finally {
         if (needUpdate) {
           updateOrderEntriesInEditors();
diff --git a/java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/projectRoot/daemon/LibraryProjectStructureElement.java b/java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/projectRoot/daemon/LibraryProjectStructureElement.java
index 62faa16e5f06..9d64108d6bab 100644
--- a/java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/projectRoot/daemon/LibraryProjectStructureElement.java
+++ b/java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/projectRoot/daemon/LibraryProjectStructureElement.java
@@ -8,9 +8,12 @@ import com.intellij.openapi.roots.impl.libraries.LibraryImpl;
 import com.intellij.openapi.roots.libraries.Library;
 import com.intellij.openapi.roots.libraries.LibraryTable;
 import com.intellij.openapi.roots.libraries.LibraryTablesRegistrar;
+import com.intellij.openapi.roots.ui.configuration.ModuleEditor;
 import com.intellij.openapi.roots.ui.configuration.projectRoot.StructureConfigurableContext;
 import org.jetbrains.annotations.NotNull;
 
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Proxy;
 import java.util.Collections;
 import java.util.List;
 
@@ -58,7 +61,10 @@ public class LibraryProjectStructureElement extends ProjectStructureElement {
 
   @NotNull 
   private Library getSourceOrThis() {
-    final Library source = ((LibraryImpl)myLibrary).getSource();
+    final InvocationHandler invocationHandler = Proxy.isProxyClass(myLibrary.getClass()) ? Proxy.getInvocationHandler(myLibrary) : null;
+    final Library realLibrary = invocationHandler instanceof ModuleEditor.ProxyDelegateAccessor ?
+                                (Library)((ModuleEditor.ProxyDelegateAccessor)invocationHandler).getDelegate() : myLibrary;
+    final Library source = realLibrary instanceof LibraryImpl? ((LibraryImpl)realLibrary).getSource() : null;
     return source != null ? source : myLibrary;
   }