diff --git a/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointClassGroup.java b/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointClassGroup.java
index 477e2d3cfca1..ca978304202e 100644
--- a/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointClassGroup.java
+++ b/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointClassGroup.java
@@ -17,7 +17,6 @@ package com.intellij.debugger.ui;
 
 import com.intellij.debugger.DebuggerBundle;
 import com.intellij.util.PlatformIcons;
-import com.intellij.xdebugger.XDebuggerBundle;
 import com.intellij.xdebugger.breakpoints.ui.XBreakpointGroup;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -26,13 +25,6 @@ import javax.swing.*;
 
 public class XBreakpointClassGroup extends XBreakpointGroup {
   private static final String DEFAULT_PACKAGE_NAME = DebuggerBundle.message("default.package.name");
-  public static final XBreakpointClassGroup UNKNOWN = new XBreakpointClassGroup("", "") {
-    @NotNull
-    @Override
-    public String getName() {
-      return XDebuggerBundle.message("xbreakpoint.group.unknown");
-    }
-  };
 
   private String myPackageName;
   private String myClassName;
diff --git a/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointGroupingByClassRule.java b/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointGroupingByClassRule.java
index 50c70fba17a1..fc3a179da2e8 100644
--- a/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointGroupingByClassRule.java
+++ b/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointGroupingByClassRule.java
@@ -42,18 +42,17 @@ class XBreakpointGroupingByClassRule<B> extends XBreakpointGroupingRule<B, XBrea
     return XBreakpointsGroupingPriorities.BY_CLASS;
   }
 
-  @NotNull
   @Override
   public XBreakpointClassGroup getGroup(@NotNull B b, @NotNull Collection<XBreakpointClassGroup> groups) {
     if (b instanceof XBreakpoint) {
       Breakpoint javaBreakpoint = BreakpointManager.findBreakpoint((XBreakpoint)b);
       if (javaBreakpoint == null) {
-        return XBreakpointClassGroup.UNKNOWN;
+        return null;
       }
       String className = javaBreakpoint.getShortClassName();
       String packageName = javaBreakpoint.getPackageName();
       if (className == null) {
-        return XBreakpointClassGroup.UNKNOWN;
+        return null;
       }
       for (XBreakpointClassGroup group : groups) {
         if (group.getClassName().equals(className) && group.getPackageName().equals(packageName))  {
@@ -62,7 +61,7 @@ class XBreakpointGroupingByClassRule<B> extends XBreakpointGroupingRule<B, XBrea
       }
       return new XBreakpointClassGroup(packageName, className);
     }
-    return XBreakpointClassGroup.UNKNOWN;
+    return null;
   }
 
   @Nullable
diff --git a/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointGroupingByPackageRule.java b/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointGroupingByPackageRule.java
index f309e85e26b2..f0df3fec2471 100644
--- a/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointGroupingByPackageRule.java
+++ b/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointGroupingByPackageRule.java
@@ -39,7 +39,6 @@ public class XBreakpointGroupingByPackageRule<B> extends XBreakpointGroupingRule
     return XBreakpointsGroupingPriorities.BY_PACKAGE;
   }
 
-  @NotNull
   @Override
   public XBreakpointPackageGroup getGroup(@NotNull B breakpoint, @NotNull Collection<XBreakpointPackageGroup> groups) {
     String packageName = null;
@@ -50,7 +49,7 @@ public class XBreakpointGroupingByPackageRule<B> extends XBreakpointGroupingRule
       }
     }
     if (packageName == null) {
-      return XBreakpointPackageGroup.UNKNOWN;
+      return null;
     }
     for (XBreakpointPackageGroup group : groups) {
       if (StringUtil.equals(group.getPackageName(), packageName)) {
diff --git a/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointPackageGroup.java b/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointPackageGroup.java
index 470d56bfe506..0d193a20255b 100644
--- a/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointPackageGroup.java
+++ b/java/debugger/impl/src/com/intellij/debugger/ui/XBreakpointPackageGroup.java
@@ -18,30 +18,17 @@ package com.intellij.debugger.ui;
 import com.intellij.debugger.DebuggerBundle;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.util.PlatformIcons;
-import com.intellij.xdebugger.XDebuggerBundle;
 import com.intellij.xdebugger.breakpoints.ui.XBreakpointGroup;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
 
 public class XBreakpointPackageGroup extends XBreakpointGroup {
   private static final String DEFAULT_PACKAGE_NAME = DebuggerBundle.message("default.package.name");
-  public static final XBreakpointPackageGroup UNKNOWN = new XBreakpointPackageGroup() {
-    @NotNull
-    @Override
-    public String getName() {
-      return XDebuggerBundle.message("xbreakpoint.group.unknown");
-    }
-  };
 
   private String myPackageName;
 
-  private XBreakpointPackageGroup() {
-    myPackageName = null;
-  }
-
-  public XBreakpointPackageGroup(@NotNull String packageName) {
+  public XBreakpointPackageGroup(String packageName) {
     myPackageName = packageName;
   }
 
@@ -57,7 +44,7 @@ public class XBreakpointPackageGroup extends XBreakpointGroup {
     return StringUtil.isEmpty(packageName) ? DEFAULT_PACKAGE_NAME : packageName;
   }
 
-  @Nullable
+  @NotNull
   public String getPackageName() {
     return myPackageName;
   }
diff --git a/platform/platform-resources-en/src/messages/XDebuggerBundle.properties b/platform/platform-resources-en/src/messages/XDebuggerBundle.properties
index 63adccb02428..de89eaa7f3b3 100644
--- a/platform/platform-resources-en/src/messages/XDebuggerBundle.properties
+++ b/platform/platform-resources-en/src/messages/XDebuggerBundle.properties
@@ -44,7 +44,6 @@ xbreakpoint.master.breakpoint.none=<None>
 xbreakpoint.master.breakpoint.description=Disabled until selected breakpoint is hit:
 rule.name.group.by.file=Group by file
 xbreakpoint.default.display.text=Line {0} in {1}
-xbreakpoint.group.unknown=Unknown
 
 xbreakpoint.reached.text=Breakpoint reached:
 
diff --git a/platform/xdebugger-api/src/com/intellij/xdebugger/breakpoints/ui/XBreakpointGroupingRule.java b/platform/xdebugger-api/src/com/intellij/xdebugger/breakpoints/ui/XBreakpointGroupingRule.java
index 650e295ad087..1038747be2c0 100644
--- a/platform/xdebugger-api/src/com/intellij/xdebugger/breakpoints/ui/XBreakpointGroupingRule.java
+++ b/platform/xdebugger-api/src/com/intellij/xdebugger/breakpoints/ui/XBreakpointGroupingRule.java
@@ -53,7 +53,7 @@ public abstract class XBreakpointGroupingRule<B, G extends XBreakpointGroup> {
     return XBreakpointsGroupingPriorities.DEFAULT;
   }
 
-  @NotNull
+  @Nullable
   public abstract G getGroup(@NotNull B breakpoint, @NotNull Collection<G> groups);
 
   @Nullable
diff --git a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointFileGroup.java b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointFileGroup.java
index c86b5e30bd28..f7ae89a202a9 100644
--- a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointFileGroup.java
+++ b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointFileGroup.java
@@ -15,11 +15,9 @@
  */
 package com.intellij.xdebugger.impl.breakpoints.ui.grouping;
 
-import com.intellij.icons.AllIcons;
 import com.intellij.ide.presentation.VirtualFilePresentation;
-import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.xdebugger.XDebuggerBundle;
 import com.intellij.xdebugger.breakpoints.ui.XBreakpointGroup;
+import com.intellij.openapi.vfs.VirtualFile;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -29,26 +27,8 @@ import javax.swing.*;
  * @author nik
  */
 public class XBreakpointFileGroup extends XBreakpointGroup {
-  public static final XBreakpointFileGroup UNKNOWN = new XBreakpointFileGroup() {
-    @NotNull
-    @Override
-    public String getName() {
-      return XDebuggerBundle.message("xbreakpoint.group.unknown");
-    }
-
-    @Nullable
-    @Override
-    public Icon getIcon(boolean isOpen) {
-      return AllIcons.FileTypes.Text;
-    }
-  };
-
   private final VirtualFile myFile;
 
-  private XBreakpointFileGroup() {
-    myFile = null;
-  }
-
   public XBreakpointFileGroup(@NotNull VirtualFile file) {
     myFile = file;
   }
@@ -63,7 +43,6 @@ public class XBreakpointFileGroup extends XBreakpointGroup {
     return myFile.getPresentableUrl();
   }
 
-  @Nullable
   public VirtualFile getFile() {
     return myFile;
   }
diff --git a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointFileGroupingRule.java b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointFileGroupingRule.java
index 44afa0fe3c88..b0b5998ef71f 100644
--- a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointFileGroupingRule.java
+++ b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointFileGroupingRule.java
@@ -16,7 +16,6 @@
 package com.intellij.xdebugger.impl.breakpoints.ui.grouping;
 
 import com.intellij.icons.AllIcons;
-import com.intellij.openapi.util.Comparing;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.xdebugger.XDebuggerBundle;
 import com.intellij.xdebugger.XSourcePosition;
@@ -42,20 +41,17 @@ public class XBreakpointFileGroupingRule<B> extends XBreakpointGroupingRule<B, X
     return XBreakpointsGroupingPriorities.BY_FILE;
   }
 
-  @NotNull
   public XBreakpointFileGroup getGroup(@NotNull final B breakpoint, @NotNull final Collection<XBreakpointFileGroup> groups) {
     if (!(breakpoint instanceof XLineBreakpoint)) {
-      return XBreakpointFileGroup.UNKNOWN;
+      return null;
     }
     XSourcePosition position = ((XLineBreakpoint)breakpoint).getSourcePosition();
 
-    if (position == null) {
-      return XBreakpointFileGroup.UNKNOWN;
-    }
+    if (position == null) return null;
 
     VirtualFile file = position.getFile();
     for (XBreakpointFileGroup group : groups) {
-      if (Comparing.equal(group.getFile(), file)) {
+      if (group.getFile().equals(file)) {
         return group;
       }
     }
diff --git a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointGroupingByTypeRule.java b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointGroupingByTypeRule.java
index 19c9018ee270..5d1301604f72 100644
--- a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointGroupingByTypeRule.java
+++ b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointGroupingByTypeRule.java
@@ -45,7 +45,6 @@ public class XBreakpointGroupingByTypeRule<B> extends XBreakpointGroupingRule<B,
     return XBreakpointsGroupingPriorities.BY_TYPE;
   }
 
-  @NotNull
   @Override
   public XBreakpointTypeGroup getGroup(@NotNull B b, @NotNull Collection<XBreakpointTypeGroup> groups) {
     if (b instanceof XBreakpoint) {
@@ -57,6 +56,6 @@ public class XBreakpointGroupingByTypeRule<B> extends XBreakpointGroupingRule<B,
       }
       return new XBreakpointTypeGroup(breakpoint.getType());
     }
-    return XBreakpointTypeGroup.UNKNOWN;
+    return null;
   }
 }
diff --git a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointTypeGroup.java b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointTypeGroup.java
index b13570ae54d7..f1dd95cc47b0 100644
--- a/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointTypeGroup.java
+++ b/platform/xdebugger-impl/src/com/intellij/xdebugger/impl/breakpoints/ui/grouping/XBreakpointTypeGroup.java
@@ -15,31 +15,17 @@
  */
 package com.intellij.xdebugger.impl.breakpoints.ui.grouping;
 
-import com.intellij.icons.AllIcons;
 import com.intellij.util.ArrayUtil;
-import com.intellij.xdebugger.XDebuggerBundle;
 import com.intellij.xdebugger.breakpoints.XBreakpointType;
+import com.intellij.xdebugger.breakpoints.XLineBreakpoint;
 import com.intellij.xdebugger.breakpoints.XLineBreakpointType;
 import com.intellij.xdebugger.breakpoints.ui.XBreakpointGroup;
 import com.intellij.xdebugger.impl.breakpoints.XBreakpointUtil;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
 
 public class XBreakpointTypeGroup extends XBreakpointGroup {
-  public static final XBreakpointTypeGroup UNKNOWN = new XBreakpointTypeGroup(null) {
-    @NotNull
-    @Override
-    public String getName() {
-      return XDebuggerBundle.message("xbreakpoint.group.unknown");
-    }
-
-    @Override
-    public Icon getIcon(boolean isOpen) {
-      return AllIcons.Debugger.Db_set_breakpoint;
-    }
-  };
 
   private XBreakpointType myBreakpointType;
 
@@ -53,7 +39,6 @@ public class XBreakpointTypeGroup extends XBreakpointGroup {
     return myBreakpointType.getTitle();
   }
 
-  @Nullable
   public XBreakpointType getBreakpointType() {
     return myBreakpointType;
   }