diff --git a/python/helpers/pydev/pydevd_frame.py b/python/helpers/pydev/pydevd_frame.py
index 0d270276bbe9..85c566346eab 100644
--- a/python/helpers/pydev/pydevd_frame.py
+++ b/python/helpers/pydev/pydevd_frame.py
@@ -97,7 +97,7 @@ class PyDBFrame:
                 return None
 
             if event == 'call':
-                sendSignatureCallTrace(mainDebugger, frame)
+                sendSignatureCallTrace(mainDebugger, frame, filename)
 
             if event not in ('line', 'call', 'return'):
                 if event == 'exception':
diff --git a/python/helpers/pydev/pydevd_signature.py b/python/helpers/pydev/pydevd_signature.py
index 77559b35ae88..6ec3dc8bcbe5 100644
--- a/python/helpers/pydev/pydevd_signature.py
+++ b/python/helpers/pydev/pydevd_signature.py
@@ -1,5 +1,7 @@
 import inspect
 import trace
+import os
+
 trace._warn = lambda *args: None   # workaround for http://bugs.python.org/issue17143 (PY-8706)
 import gc
 from pydevd_comm import CMD_SIGNATURE_CALL_TRACE, NetCommand
@@ -23,6 +25,17 @@ class Signature(object):
 class SignatureFactory(object):
     def __init__(self):
         self._caller_cache = {}
+        self.project_roots =  os.getenv('PYCHARM_PROJECT_ROOTS', '').split(os.pathsep)
+
+    def is_in_scope(self, filename):
+        filename = normcase(realpath(filename))
+        for root in self.project_roots:
+            root = normcase(realpath(root))
+            if filename.startsWith(root):
+                return True
+        return False
+
+
 
     def create_signature(self, frame):
         try:
@@ -109,9 +122,10 @@ def create_signature_message(signature):
     cmdText = ''.join(cmdTextList)
     return NetCommand(CMD_SIGNATURE_CALL_TRACE, 0, cmdText)
 
-def sendSignatureCallTrace(dbg, frame):
+def sendSignatureCallTrace(dbg, frame, filename):
     if dbg.signature_factory:
-        dbg.writer.addCommand(create_signature_message(dbg.signature_factory.create_signature(frame)))
+        if dbg.signature_factory.is_in_scope(filename):
+            dbg.writer.addCommand(create_signature_message(dbg.signature_factory.create_signature(frame)))
 
 
 
diff --git a/python/src/com/jetbrains/python/debugger/PyDebugRunner.java b/python/src/com/jetbrains/python/debugger/PyDebugRunner.java
index 70ca7dd2f2ec..62dce9f8018d 100644
--- a/python/src/com/jetbrains/python/debugger/PyDebugRunner.java
+++ b/python/src/com/jetbrains/python/debugger/PyDebugRunner.java
@@ -1,5 +1,7 @@
 package com.jetbrains.python.debugger;
 
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
 import com.intellij.execution.ExecutionException;
 import com.intellij.execution.ExecutionResult;
 import com.intellij.execution.Executor;
@@ -15,11 +17,16 @@ import com.intellij.execution.ui.RunContentDescriptor;
 import com.intellij.openapi.actionSystem.AnAction;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.fileEditor.FileDocumentManager;
+import com.intellij.openapi.module.ModuleManager;
 import com.intellij.openapi.project.Project;
+import com.intellij.openapi.roots.ProjectRootManager;
+import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.xdebugger.XDebugProcess;
 import com.intellij.xdebugger.XDebugProcessStarter;
 import com.intellij.xdebugger.XDebugSession;
 import com.intellij.xdebugger.XDebuggerManager;
+import com.jetbrains.appengine.util.StringUtils;
 import com.jetbrains.python.PythonHelpersLocator;
 import com.jetbrains.python.console.PythonConsoleView;
 import com.jetbrains.python.console.PythonDebugConsoleCommunication;
@@ -32,8 +39,11 @@ import com.jetbrains.python.sdk.flavors.PythonSdkFlavor;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.io.File;
 import java.net.ServerSocket;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 /**
  * @author yole
@@ -45,6 +55,7 @@ public class PyDebugRunner extends GenericProgramRunner {
   public static final String CLIENT_PARAM = "--client";
   public static final String PORT_PARAM = "--port";
   public static final String FILE_PARAM = "--file";
+  public static final String PYCHARM_PROJECT_ROOTS = "PYCHARM_PROJECT_ROOTS";
 
   @NotNull
   public String getRunnerId() {
@@ -139,7 +150,9 @@ public class PyDebugRunner extends GenericProgramRunner {
     return new CommandLinePatcher[]{createDebugServerPatcher(project, state, serverLocalPort), createRunConfigPatcher(state, profile)};
   }
 
-  private static CommandLinePatcher createDebugServerPatcher(final Project project, final PythonCommandLineState pyState, final int serverLocalPort) {
+  private static CommandLinePatcher createDebugServerPatcher(final Project project,
+                                                             final PythonCommandLineState pyState,
+                                                             final int serverLocalPort) {
     return new CommandLinePatcher() {
       public void patchCommandLine(GeneralCommandLine commandLine) {
 
@@ -160,12 +173,16 @@ public class PyDebugRunner extends GenericProgramRunner {
           }
         }
 
-        fillDebugParameters(project, debugParams, serverLocalPort, pyState);
+        fillDebugParameters(project, debugParams, serverLocalPort, pyState, commandLine);
       }
     };
   }
 
-  private static void fillDebugParameters(Project project, ParamsGroup debugParams, int serverLocalPort, PythonCommandLineState pyState) {
+  private static void fillDebugParameters(@NotNull Project project,
+                                          @NotNull ParamsGroup debugParams,
+                                          int serverLocalPort,
+                                          @NotNull PythonCommandLineState pyState,
+                                          @NotNull GeneralCommandLine generalCommandLine) {
     debugParams.addParameter(PythonHelpersLocator.getHelperPath(DEBUGGER_MAIN));
     if (pyState.isMultiprocessDebug()) {
       debugParams.addParameter("--multiproc");
@@ -177,6 +194,7 @@ public class PyDebugRunner extends GenericProgramRunner {
 
     if (PyDebuggerOptionsProvider.getInstance(project).isSaveCallSignatures()) {
       debugParams.addParameter("--save-signatures");
+      addProjectRootsToEnv(project, generalCommandLine);
     }
 
     final String[] debuggerArgs = new String[]{
@@ -188,4 +206,20 @@ public class PyDebugRunner extends GenericProgramRunner {
       debugParams.addParameter(s);
     }
   }
+
+  private static void addProjectRootsToEnv(@NotNull Project project, @NotNull GeneralCommandLine commandLine) {
+    Map<String, String> params = commandLine.getEnvParams();
+
+    if (params == null) {
+      params = Maps.newHashMap();
+      commandLine.setEnvParams(params);
+    }
+
+    List<String> roots = Lists.newArrayList();
+    for (VirtualFile contentRoot : ProjectRootManager.getInstance(project).getContentRoots()) {
+      roots.add(contentRoot.getPath());
+    }
+
+    params.put(PYCHARM_PROJECT_ROOTS, StringUtil.join(roots, File.pathSeparator));
+  }
 }
diff --git a/python/src/com/jetbrains/python/sdk/PythonEnvUtil.java b/python/src/com/jetbrains/python/sdk/PythonEnvUtil.java
index 015c04759b02..4b5df7b1e20c 100644
--- a/python/src/com/jetbrains/python/sdk/PythonEnvUtil.java
+++ b/python/src/com/jetbrains/python/sdk/PythonEnvUtil.java
@@ -62,7 +62,7 @@ public class PythonEnvUtil {
       assert source != null;
       Set<String> vals = Sets.newHashSet(source.split(File.pathSeparator));
       if (!vals.contains(value)) {
-        return source + File.pathSeparatorChar + value;
+        return source + File.pathSeparator + value;
       }
       else {
         return source;
@@ -73,11 +73,11 @@ public class PythonEnvUtil {
 
   public static void addToEnv(Map<String, String> envs, String key, Collection<String> values) {
     for (String val : values) {
-      addToEnv(envs, key, val);
+      addPathToEnv(envs, key, val);
     }
   }
 
-  public static void addToEnv(Map<String, String> envs, String key, String value) {
+  public static void addPathToEnv(Map<String, String> envs, String key, String value) {
     if (!StringUtil.isEmpty(value)) {
       if (envs.containsKey(key)) {
         envs.put(key, appendToPathEnvVar(envs.get(key), value));
@@ -93,13 +93,17 @@ public class PythonEnvUtil {
   }
 
   public static void addToPythonPath(Map<String, String> envs, String value) {
-    addToEnv(envs, PYTHONPATH, value);
+    addPathToEnv(envs, PYTHONPATH, value);
   }
 
 
   @Nullable
   public static List<String> getPythonPathList(Map<String, String> envs) {
-    String pythonPath = envs.get(PYTHONPATH);
+    return getPathListFromEnv(envs, PYTHONPATH);
+  }
+
+  public static List<String> getPathListFromEnv(Map<String, String> envs, String envKey) {
+    String pythonPath = envs.get(envKey);
     if (pythonPath != null) {
       String[] paths = pythonPath.split(Character.toString(File.pathSeparatorChar));
       return Lists.newArrayList(paths);
diff --git a/python/src/com/jetbrains/python/sdk/flavors/PythonSdkFlavor.java b/python/src/com/jetbrains/python/sdk/flavors/PythonSdkFlavor.java
index cf77e38d3f33..e0d408761949 100644
--- a/python/src/com/jetbrains/python/sdk/flavors/PythonSdkFlavor.java
+++ b/python/src/com/jetbrains/python/sdk/flavors/PythonSdkFlavor.java
@@ -194,7 +194,7 @@ public abstract class PythonSdkFlavor {
   }
 
   public static void addToEnv(final String key, String value, Map<String, String> envs) {
-    PythonEnvUtil.addToEnv(envs, key, value);
+    PythonEnvUtil.addPathToEnv(envs, key, value);
   }
 
   static Map<String, String> getEnv(GeneralCommandLine cmd) {