diff --git a/java/testFramework/src/com/intellij/codeInsight/CodeInsightTestCase.java b/java/testFramework/src/com/intellij/codeInsight/CodeInsightTestCase.java
index 3fea6249054e..0238f601e11b 100644
--- a/java/testFramework/src/com/intellij/codeInsight/CodeInsightTestCase.java
+++ b/java/testFramework/src/com/intellij/codeInsight/CodeInsightTestCase.java
@@ -18,6 +18,8 @@ package com.intellij.codeInsight;
 import com.intellij.codeInsight.highlighting.HighlightUsagesHandler;
 import com.intellij.ide.DataManager;
 import com.intellij.injected.editor.EditorWindow;
+import com.intellij.javaee.ExternalResourceManager;
+import com.intellij.openapi.Disposable;
 import com.intellij.openapi.actionSystem.*;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.application.Result;
@@ -40,6 +42,7 @@ import com.intellij.openapi.fileTypes.FileTypeManager;
 import com.intellij.openapi.roots.ContentEntry;
 import com.intellij.openapi.roots.ModifiableRootModel;
 import com.intellij.openapi.roots.ModuleRootManager;
+import com.intellij.openapi.util.Disposer;
 import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.openapi.vfs.LocalFileSystem;
@@ -704,4 +707,22 @@ public abstract class CodeInsightTestCase extends PsiTestCase {
     assertNotNull("Package " + name + " not found", aPackage);
     return aPackage;
   }
+  protected void registerResourceTemporarily(final String url, final String location) {
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        ExternalResourceManager.getInstance().addResource(url, location);
+      }
+    });
+
+    Disposer.register(getTestRootDisposable(), new Disposable() {
+      @Override
+      public void dispose() {
+        ApplicationManager.getApplication().runWriteAction(new Runnable() {
+          public void run() {
+            ExternalResourceManager.getInstance().removeResource(url);
+          }
+        });
+      }
+    });
+  }
 }
diff --git a/plugins/properties/testSrc/com/intellij/lang/properties/PropertiesFileTest.java b/plugins/properties/testSrc/com/intellij/lang/properties/PropertiesFileTest.java
index 2f9db59d653e..ecf65cdb9861 100644
--- a/plugins/properties/testSrc/com/intellij/lang/properties/PropertiesFileTest.java
+++ b/plugins/properties/testSrc/com/intellij/lang/properties/PropertiesFileTest.java
@@ -43,8 +43,13 @@ public class PropertiesFileTest extends LightPlatformTestCase {
   }
 
   public void testAddPropertyAfterComment() throws Exception {
-    PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "#xxxxx");
-    propertiesFile.addProperty(myPropertyToAdd);
+    final PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "#xxxxx");
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        propertiesFile.addProperty(myPropertyToAdd);
+      }
+    });
+
 
     List<Property> properties = propertiesFile.getProperties();
     Property added = properties.get(0);
@@ -57,8 +62,13 @@ public class PropertiesFileTest extends LightPlatformTestCase {
   }
 
   public void testAddPropertyAfterProperty() throws Exception {
-    PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "xxx=yyy");
-    propertiesFile.addProperty(myPropertyToAdd);
+    final PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "xxx=yyy");
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        propertiesFile.addProperty(myPropertyToAdd);
+      }
+    });
+
 
     List<Property> properties = propertiesFile.getProperties();
     assertEquals(2, properties.size());
@@ -112,9 +122,14 @@ public class PropertiesFileTest extends LightPlatformTestCase {
   }
 
   public void testAddToEnd() throws IncorrectOperationException {
-    PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "a=b\\nccc");
+    final PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "a=b\\nccc");
     assertEquals(1,propertiesFile.getProperties().size());
-    propertiesFile.addProperty(myPropertyToAdd);
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        propertiesFile.addProperty(myPropertyToAdd);
+      }
+    });
+
     assertEquals("a=b\\nccc\nkkk=vvv", propertiesFile.getText());
   }
 
@@ -129,20 +144,35 @@ public class PropertiesFileTest extends LightPlatformTestCase {
   }
 
   public void testAddPropertyAfter() throws IncorrectOperationException {
-    PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "a=b\nc=d\ne=f");
-    Property c = propertiesFile.findPropertyByKey("c");
-    propertiesFile.addPropertyAfter(myPropertyToAdd, c);
+    final PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "a=b\nc=d\ne=f");
+    final Property c = propertiesFile.findPropertyByKey("c");
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        propertiesFile.addPropertyAfter(myPropertyToAdd, c);
+      }
+    });
+
     assertEquals("a=b\nc=d\nkkk=vvv\ne=f", propertiesFile.getText());
   }
   public void testAddPropertyAfterLast() throws IncorrectOperationException {
-    PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "a=b\nc=d\ne=f");
-    Property p = propertiesFile.findPropertyByKey("e");
-    propertiesFile.addPropertyAfter(myPropertyToAdd, p);
+    final PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "a=b\nc=d\ne=f");
+    final Property p = propertiesFile.findPropertyByKey("e");
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        propertiesFile.addPropertyAfter(myPropertyToAdd, p);
+      }
+    });
+
     assertEquals("a=b\nc=d\ne=f\nkkk=vvv", propertiesFile.getText());
   }
   public void testAddPropertyAfterInBeginning() throws IncorrectOperationException {
-    PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "a=b\nc=d\ne=f");
-    propertiesFile.addPropertyAfter(myPropertyToAdd, null);
+    final PropertiesFile propertiesFile = PropertiesElementFactory.createPropertiesFile(getProject(), "a=b\nc=d\ne=f");
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        propertiesFile.addPropertyAfter(myPropertyToAdd, null);
+      }
+    });
+
     assertEquals("kkk=vvv\na=b\nc=d\ne=f", propertiesFile.getText());
   }
   public void testUnescapedKey() throws IncorrectOperationException {
diff --git a/plugins/relaxng/test/org/intellij/plugins/relaxNG/HighlightingTestBase.java b/plugins/relaxng/test/org/intellij/plugins/relaxNG/HighlightingTestBase.java
index 2b6108f13645..7c7c2dcf3d01 100644
--- a/plugins/relaxng/test/org/intellij/plugins/relaxNG/HighlightingTestBase.java
+++ b/plugins/relaxng/test/org/intellij/plugins/relaxNG/HighlightingTestBase.java
@@ -24,6 +24,7 @@ import com.intellij.codeInspection.InspectionToolProvider;
 import com.intellij.codeInspection.htmlInspections.RequiredAttributesInspection;
 import com.intellij.javaee.ExternalResourceManagerEx;
 import com.intellij.mock.MockProgressIndicator;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.application.PluginPathManager;
 import com.intellij.openapi.application.Result;
 import com.intellij.openapi.application.WriteAction;
@@ -158,7 +159,11 @@ public abstract class HighlightingTestBase extends UsefulTestCase implements Ide
   public abstract String getTestDataPath();
 
   protected void init() {
-    ExternalResourceManagerEx.getInstanceEx().addIgnoredResource("urn:test:undefined");
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        ExternalResourceManagerEx.getInstanceEx().addIgnoredResource("urn:test:undefined");
+      }
+    });
   }
 
   protected void tearDown() throws Exception {
diff --git a/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngHtml5CompletionTest.java b/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngHtml5CompletionTest.java
index f1c813eeeab6..7fe2b870dce3 100644
--- a/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngHtml5CompletionTest.java
+++ b/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngHtml5CompletionTest.java
@@ -16,6 +16,7 @@
 package org.intellij.plugins.relaxNG;
 
 import com.intellij.javaee.ExternalResourceManagerEx;
+import com.intellij.openapi.application.ApplicationManager;
 
 /**
  * @author Eugene.Kudelevsky
@@ -32,8 +33,12 @@ public class RngHtml5CompletionTest extends HighlightingTestBase {
   protected void init() {
     super.init();
 
-    final ExternalResourceManagerEx m = ExternalResourceManagerEx.getInstanceEx();
-    m.addResource("http://www.w3.org/1999/xhtml/html5", toAbsolutePath("/highlighting/html5/html5.rnc"));
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        final ExternalResourceManagerEx m = ExternalResourceManagerEx.getInstanceEx();
+        m.addResource("http://www.w3.org/1999/xhtml/html5", toAbsolutePath("/highlighting/html5/html5.rnc"));
+      }
+    });
   }
 
   public void testHtml5_1() throws Throwable {
diff --git a/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngXmlHighlightingTest.java b/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngXmlHighlightingTest.java
index 57f6a875f0c2..b21f37c0ee78 100644
--- a/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngXmlHighlightingTest.java
+++ b/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngXmlHighlightingTest.java
@@ -17,6 +17,7 @@
 package org.intellij.plugins.relaxNG;
 
 import com.intellij.javaee.ExternalResourceManagerEx;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.fileTypes.FileTypeManager;
 import com.intellij.openapi.fileTypes.StdFileTypes;
 import org.intellij.plugins.testUtil.CopyFile;
@@ -36,26 +37,30 @@ public class RngXmlHighlightingTest extends HighlightingTestBase {
     super.init();
     FileTypeManager.getInstance().registerFileType(StdFileTypes.XML, "fo");
 
-    final ExternalResourceManagerEx m = ExternalResourceManagerEx.getInstanceEx();
-    m.addResource("urn:test:simple.rng", toAbsolutePath("highlighting/simple.rng"));
-    m.addResource("urn:test:addressBook", toAbsolutePath("highlighting/rnc/addressbook.rnc"));
-    m.addResource("http://www.w3.org/1999/XSL/Transform", toAbsolutePath("highlighting/relaxng.rng"));
-    m.addResource("http://www.w3.org/1999/XSL/Format", toAbsolutePath("highlighting/rnc/fo/main.rnc"));
-    m.addResource("http://docbook.org/ns/docbook", toAbsolutePath("highlighting/docbook.rng"));
-    m.addResource("urn:intelliForm:AttachmentFilter", toAbsolutePath("highlighting/attachment-filter.rng"));
-    m.addResource("http://www.w3.org/1999/xhtml/html5", toAbsolutePath("highlighting/html5/xhtml5.rnc"));
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        final ExternalResourceManagerEx m = ExternalResourceManagerEx.getInstanceEx();
+        m.addResource("urn:test:simple.rng", toAbsolutePath("highlighting/simple.rng"));
+        m.addResource("urn:test:addressBook", toAbsolutePath("highlighting/rnc/addressbook.rnc"));
+        m.addResource("http://www.w3.org/1999/XSL/Transform", toAbsolutePath("highlighting/relaxng.rng"));
+        m.addResource("http://www.w3.org/1999/XSL/Format", toAbsolutePath("highlighting/rnc/fo/main.rnc"));
+        m.addResource("http://docbook.org/ns/docbook", toAbsolutePath("highlighting/docbook.rng"));
+        m.addResource("urn:intelliForm:AttachmentFilter", toAbsolutePath("highlighting/attachment-filter.rng"));
+        m.addResource("http://www.w3.org/1999/xhtml/html5", toAbsolutePath("highlighting/html5/xhtml5.rnc"));
 
-    m.addIgnoredResource("urn:intelliForm:Spaces");
-    m.addIgnoredResource("http://www.w3.org/1999/xlink");
-    m.addIgnoredResource("http://www.w3.org/2000/svg");
-    m.addIgnoredResource("http://www.ascc.net/xml/schematron");
-    m.addIgnoredResource("http://www.w3.org/2000/svg");
-    m.addIgnoredResource("http://www.w3.org/1998/Math/MathML");
-    m.addIgnoredResource("http://nwalsh.com/xmlns/schema-control/");
-    m.addIgnoredResource("http://xml.apache.org/fop/extensions");
-    m.addIgnoredResource("http://www.antennahouse.com/names/XSL/Extensions");
-    m.addIgnoredResource("http://www.renderx.com/XSL/Extensions");
-    m.addIgnoredResource("http://relaxng.org/ns/compatibility/annotations/1.0");
+        m.addIgnoredResource("urn:intelliForm:Spaces");
+        m.addIgnoredResource("http://www.w3.org/1999/xlink");
+        m.addIgnoredResource("http://www.w3.org/2000/svg");
+        m.addIgnoredResource("http://www.ascc.net/xml/schematron");
+        m.addIgnoredResource("http://www.w3.org/2000/svg");
+        m.addIgnoredResource("http://www.w3.org/1998/Math/MathML");
+        m.addIgnoredResource("http://nwalsh.com/xmlns/schema-control/");
+        m.addIgnoredResource("http://xml.apache.org/fop/extensions");
+        m.addIgnoredResource("http://www.antennahouse.com/names/XSL/Extensions");
+        m.addIgnoredResource("http://www.renderx.com/XSL/Extensions");
+        m.addIgnoredResource("http://relaxng.org/ns/compatibility/annotations/1.0");
+      }
+    });
   }
 
   public void testSimpleElement() throws Throwable {
diff --git a/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngXmlValidationTest.java b/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngXmlValidationTest.java
index 3aa5c11d84ed..d870ea18fe06 100644
--- a/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngXmlValidationTest.java
+++ b/plugins/relaxng/test/org/intellij/plugins/relaxNG/RngXmlValidationTest.java
@@ -17,6 +17,7 @@
 package org.intellij.plugins.relaxNG;
 
 import com.intellij.javaee.ExternalResourceManager;
+import com.intellij.openapi.application.ApplicationManager;
 import org.intellij.plugins.testUtil.CopyFile;
 
 /**
@@ -84,10 +85,14 @@ public class RngXmlValidationTest extends HighlightingTestBase {
 
   protected void init() {
     super.init();
-    final ExternalResourceManager mgr = ExternalResourceManager.getInstance();
-    mgr.addResource("urn:test:simple.rng", toAbsolutePath("validation/simple.rng"));
-    mgr.addResource("urn:test:simple.rnc", toAbsolutePath("validation/simple.rnc"));
-    mgr.addResource("http://www.w3.org/1999/XSL/Transform", toAbsolutePath("validation/relaxng.rng"));
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        final ExternalResourceManager mgr = ExternalResourceManager.getInstance();
+        mgr.addResource("urn:test:simple.rng", toAbsolutePath("validation/simple.rng"));
+        mgr.addResource("urn:test:simple.rnc", toAbsolutePath("validation/simple.rnc"));
+        mgr.addResource("http://www.w3.org/1999/XSL/Transform", toAbsolutePath("validation/relaxng.rng"));
+      }
+    });
   }
 
   public String getTestDataPath() {
diff --git a/plugins/xpath/xpath-lang/test/org/intellij/lang/xpath/xslt/Xslt2HighlightingTest.java b/plugins/xpath/xpath-lang/test/org/intellij/lang/xpath/xslt/Xslt2HighlightingTest.java
index 96e576dea89a..41987db3c862 100644
--- a/plugins/xpath/xpath-lang/test/org/intellij/lang/xpath/xslt/Xslt2HighlightingTest.java
+++ b/plugins/xpath/xpath-lang/test/org/intellij/lang/xpath/xslt/Xslt2HighlightingTest.java
@@ -16,6 +16,7 @@
 package org.intellij.lang.xpath.xslt;
 
 import com.intellij.javaee.ExternalResourceManagerEx;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.util.ArrayUtil;
 import org.intellij.lang.xpath.TestBase;
 import org.intellij.lang.xpath.xslt.impl.XsltStuffProvider;
@@ -30,8 +31,12 @@ public class Xslt2HighlightingTest extends TestBase {
   protected void setUp() throws Exception {
     super.setUp();
     myFixture.enableInspections(XsltStuffProvider.INSPECTION_CLASSES);
-    ExternalResourceManagerEx.getInstanceEx().addIgnoredResource("urn:my");
-    ExternalResourceManagerEx.getInstanceEx().addIgnoredResource("nsx");
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        ExternalResourceManagerEx.getInstanceEx().addIgnoredResource("urn:my");
+        ExternalResourceManagerEx.getInstanceEx().addIgnoredResource("nsx");
+      }
+    });
   }
 
   public void testCurrentMode() throws Throwable {
diff --git a/plugins/xpath/xpath-lang/test/org/intellij/lang/xpath/xslt/XsltHighlightingTest.java b/plugins/xpath/xpath-lang/test/org/intellij/lang/xpath/xslt/XsltHighlightingTest.java
index 9a7f4c1e6841..0797b78d4811 100644
--- a/plugins/xpath/xpath-lang/test/org/intellij/lang/xpath/xslt/XsltHighlightingTest.java
+++ b/plugins/xpath/xpath-lang/test/org/intellij/lang/xpath/xslt/XsltHighlightingTest.java
@@ -36,7 +36,11 @@ public class XsltHighlightingTest extends TestBase {
     protected void setUp() throws Exception {
         super.setUp();
         myFixture.enableInspections(XsltStuffProvider.INSPECTION_CLASSES);
-        ExternalResourceManagerEx.getInstanceEx().addIgnoredResource("urn:my");
+      ApplicationManager.getApplication().runWriteAction(new Runnable() {
+        public void run() {
+          ExternalResourceManagerEx.getInstanceEx().addIgnoredResource("urn:my");
+        }
+      });
     }
 
     public void xtestBackwardIncludedVariable() throws Throwable {
diff --git a/xml/impl/src/com/intellij/codeInsight/daemon/impl/quickfix/IgnoreExtResourceAction.java b/xml/impl/src/com/intellij/codeInsight/daemon/impl/quickfix/IgnoreExtResourceAction.java
index 2a1c2299d93d..54d922bcb14c 100644
--- a/xml/impl/src/com/intellij/codeInsight/daemon/impl/quickfix/IgnoreExtResourceAction.java
+++ b/xml/impl/src/com/intellij/codeInsight/daemon/impl/quickfix/IgnoreExtResourceAction.java
@@ -16,9 +16,11 @@
 package com.intellij.codeInsight.daemon.impl.quickfix;
 
 import com.intellij.javaee.ExternalResourceManagerEx;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.psi.PsiFile;
 import com.intellij.openapi.editor.Editor;
 import com.intellij.util.IncorrectOperationException;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * @author mike
@@ -28,7 +30,11 @@ public class IgnoreExtResourceAction extends BaseExtResourceAction {
     return "ignore.external.resource.text";
   }
 
-  protected void doInvoke(final PsiFile file, final int offset, final String uri, final Editor editor) throws IncorrectOperationException {
-    ExternalResourceManagerEx.getInstanceEx().addIgnoredResource(uri);
+  protected void doInvoke(@NotNull final PsiFile file, final int offset, @NotNull final String uri, final Editor editor) throws IncorrectOperationException {
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        ExternalResourceManagerEx.getInstanceEx().addIgnoredResource(uri);
+      }
+    });
   }
 }
diff --git a/xml/impl/src/com/intellij/codeInsight/daemon/impl/quickfix/ManuallySetupExtResourceAction.java b/xml/impl/src/com/intellij/codeInsight/daemon/impl/quickfix/ManuallySetupExtResourceAction.java
index e2ff6e831beb..6558a45e209f 100644
--- a/xml/impl/src/com/intellij/codeInsight/daemon/impl/quickfix/ManuallySetupExtResourceAction.java
+++ b/xml/impl/src/com/intellij/codeInsight/daemon/impl/quickfix/ManuallySetupExtResourceAction.java
@@ -17,6 +17,7 @@ package com.intellij.codeInsight.daemon.impl.quickfix;
 
 import com.intellij.javaee.ExternalResourceConfigurable;
 import com.intellij.javaee.ExternalResourceManager;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.options.ShowSettingsUtil;
 import com.intellij.openapi.project.Project;
@@ -34,7 +35,12 @@ public class ManuallySetupExtResourceAction extends BaseExtResourceAction {
   }
 
   protected void doInvoke(@NotNull final PsiFile file, final int offset, @NotNull final String uri, final Editor editor) throws IncorrectOperationException {
-    ExternalResourceManager.getInstance().addResource(uri,"");
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        ExternalResourceManager.getInstance().addResource(uri, "");
+      }
+    });
+
     final Project project = file.getProject();
     final ExternalResourceConfigurable component = new ExternalResourceConfigurable(project);
     ShowSettingsUtil.getInstance().editConfigurable(project, component, new Runnable() {
diff --git a/xml/impl/src/com/intellij/javaee/ExternalResourceConfigurable.java b/xml/impl/src/com/intellij/javaee/ExternalResourceConfigurable.java
index 6a4b80ca2f99..9fd80b66ea6d 100644
--- a/xml/impl/src/com/intellij/javaee/ExternalResourceConfigurable.java
+++ b/xml/impl/src/com/intellij/javaee/ExternalResourceConfigurable.java
@@ -15,6 +15,7 @@
  */
 package com.intellij.javaee;
 
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.options.BaseConfigurable;
 import com.intellij.openapi.options.OptionalConfigurable;
 import com.intellij.openapi.options.SearchableConfigurable;
@@ -139,24 +140,30 @@ public class ExternalResourceConfigurable extends BaseConfigurable implements Se
   }
 
   public void apply() {
-    ExternalResourceManagerEx manager = ExternalResourceManagerEx.getInstanceEx();
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        ExternalResourceManagerEx manager = ExternalResourceManagerEx.getInstanceEx();
 
-    manager.clearAllResources(myProject);
-    for (Object myPair : myPairs) {
-      EditLocationDialog.NameLocationPair pair = (EditLocationDialog.NameLocationPair)myPair;
-      String s = pair.myLocation.replace('\\', '/');
-      if (pair.myShared) {
-        manager.addResource(pair.myName, s);
-      } else {
-        manager.addResource(pair.myName, s, myProject);
+        manager.clearAllResources(myProject);
+        for (Object myPair : myPairs) {
+          EditLocationDialog.NameLocationPair pair = (EditLocationDialog.NameLocationPair)myPair;
+          String s = pair.myLocation.replace('\\', '/');
+          if (pair.myShared) {
+            manager.addResource(pair.myName, s);
+          }
+          else {
+            manager.addResource(pair.myName, s, myProject);
+          }
+        }
+
+        for (Object myIgnoredUrl : myIgnoredUrls) {
+          String url = (String)myIgnoredUrl;
+          manager.addIgnoredResource(url);
+        }
+        manager.setDefaultHtmlDoctype(myHtmlLanguageLevelForm.getDoctype(), myProject);
       }
-    }
+    });
 
-    for (Object myIgnoredUrl : myIgnoredUrls) {
-      String url = (String)myIgnoredUrl;
-      manager.addIgnoredResource(url);
-    }
-    manager.setDefaultHtmlDoctype(myHtmlLanguageLevelForm.getDoctype(), myProject);
     setModified(false);
   }
 
diff --git a/xml/impl/src/com/intellij/javaee/ExternalResourceManagerImpl.java b/xml/impl/src/com/intellij/javaee/ExternalResourceManagerImpl.java
index 68f06ea53f3d..2eb908a0607a 100644
--- a/xml/impl/src/com/intellij/javaee/ExternalResourceManagerImpl.java
+++ b/xml/impl/src/com/intellij/javaee/ExternalResourceManagerImpl.java
@@ -215,6 +215,7 @@ public class ExternalResourceManagerImpl extends ExternalResourceManagerEx imple
   }
 
   public void addResource(@NonNls String url, @NonNls String version, @NonNls String location) {
+    ApplicationManager.getApplication().assertWriteAccessAllowed();
     addSilently(url, version, location);
     fireExternalResourceChanged();
   }
@@ -232,6 +233,7 @@ public class ExternalResourceManagerImpl extends ExternalResourceManagerEx imple
   }
 
   public void removeResource(String url, String version) {
+    ApplicationManager.getApplication().assertWriteAccessAllowed();
     Map<String, String> map = getMap(myResources, version, false);
     if (map != null) {
       String location = map.remove(url);
@@ -272,6 +274,7 @@ public class ExternalResourceManagerImpl extends ExternalResourceManagerEx imple
   }
 
   public void clearAllResources(Project project) {
+    ApplicationManager.getApplication().assertWriteAccessAllowed();
     clearAllResources();
     getProjectResources(project).clearAllResources();
     myModificationCount++;
@@ -279,6 +282,7 @@ public class ExternalResourceManagerImpl extends ExternalResourceManagerEx imple
   }
 
   public void addIgnoredResource(String url) {
+    ApplicationManager.getApplication().assertWriteAccessAllowed();
     addIgnoredSilently(url);
     fireExternalResourceChanged();
   }
@@ -289,6 +293,7 @@ public class ExternalResourceManagerImpl extends ExternalResourceManagerEx imple
   }
 
   public void removeIgnoredResource(String url) {
+    ApplicationManager.getApplication().assertWriteAccessAllowed();
     if (myIgnoredResources.remove(url)) {
       myModificationCount++;
       fireExternalResourceChanged();
@@ -395,7 +400,7 @@ public class ExternalResourceManagerImpl extends ExternalResourceManagerEx imple
   }
 
 
-  private final static NotNullLazyKey<ProjectResources, Project> INSTANCE_CACHE = ServiceManager.createLazyKey(ProjectResources.class);
+  private static final NotNullLazyKey<ProjectResources, Project> INSTANCE_CACHE = ServiceManager.createLazyKey(ProjectResources.class);
 
   private static ExternalResourceManagerImpl getProjectResources(Project project) {
     return INSTANCE_CACHE.getValue(project);