diff --git a/src/Debug/Debug.py b/src/Debug/Debug.py
index 2e38683e..b5ac3627 100644
--- a/src/Debug/Debug.py
+++ b/src/Debug/Debug.py
@@ -22,6 +22,47 @@ def formatExceptionMessage(err):
     return "%s: %s" % (err_type, err_message)
 
 
+python_lib_dir = os.path.dirname(os.__file__)
+
+
+def formatTraceback(items, limit=None, fold_builtin=True):
+    back = []
+    i = 0
+    prev_file_title = ""
+    for path, line in items:
+        i += 1
+        is_last = i == len(items)
+        dir_name, file_name = os.path.split(path.replace("\\", "/"))
+
+        plugin_match = re.match(".*/plugins/(.+)$", dir_name)
+        if plugin_match:
+            file_title = "%s/%s" % (plugin_match.group(1), file_name)
+            is_prev_builtin = False
+        elif path.startswith(python_lib_dir):
+            if is_prev_builtin and not is_last and fold_builtin:
+                if back[-1] != "...":
+                    back.append("...")
+                continue
+            else:
+                file_title = path.replace(python_lib_dir, "").replace("\\", "/").strip("/").replace("site-packages/", "")
+            is_prev_builtin = True
+        else:
+            file_title = file_name
+            is_prev_builtin = False
+
+        if file_title == prev_file_title:
+            back.append("%s" % line)
+        else:
+            back.append("%s line %s" % (file_title, line))
+
+        prev_file_title = file_title
+
+        if limit and i >= limit:
+            back.append("...")
+            break
+    return back
+
+
 def formatException(err=None, format="text"):
     import traceback
     if type(err) == Notify:
@@ -38,35 +79,17 @@ def formatException(err=None, format="text"):
         else:
             err = exc_obj
 
-    tb = []
-    for frame in traceback.extract_tb(exc_tb):
-        path, line, function, text = frame
-        dir_name, file_name = os.path.split(path.replace("\\", "/"))
-        plugin_match = re.match(".*/plugins/(.+)$", dir_name)
-        if plugin_match:
-            file_title = "%s/%s" % (plugin_match.group(1), file_name)
-        else:
-            file_title = file_name
-        tb.append("%s line %s" % (file_title, line))
+    tb = formatTraceback([[frame[0], frame[1]] for frame in traceback.extract_tb(exc_tb)])
     if format == "html":
         return "%s: %s<br><small class='multiline'>%s</small>" % (repr(err), err, " > ".join(tb))
     else:
         return "%s: %s in %s" % (exc_type.__name__, err, " > ".join(tb))
 
 
-def formatStack(limit=99):
+def formatStack(limit=None):
     import inspect
-    back = []
-    i = 0
-    for stack in inspect.stack():
-        i += 1
-        frame, path, line, function, source, index = stack
-        file = os.path.split(path)[1]
-        back.append("%s line %s" % (file, line))
-        if i > limit:
-            back.append("...")
-            break
-    return " > ".join(back)
+    tb = formatTraceback([[frame[1], frame[2]] for frame in inspect.stack()[1:]], limit=limit)
+    return " > ".join(tb)
 
 
 # Test if gevent eventloop blocks