diff --git a/application.py b/application.py
index 940a94b..f05ece5 100755
--- a/application.py
+++ b/application.py
@@ -318,7 +318,8 @@ class Application(object):
             lines = list(candidates)
         data = '\n'.join(lines)
 
-        b             = self.data_buffer("*Completions*", data, switch_to=False)
+        b = self.data_buffer("*Completions*", data, switch_to=False)
+
         b._completion = s
         b._opened     = opened
         b._previous   = previous
diff --git a/method/__init__.py b/method/__init__.py
index ef564ad..5cf7153 100644
--- a/method/__init__.py
+++ b/method/__init__.py
@@ -490,14 +490,25 @@ class InsertTab(Method):
 
         # if no lvl, insert a literal tab
         if lvl is None:
-            w.insert_string_at_cursor(' ' * w.mode.tabwidth)
+            #w.insert_string_at_cursor(' ' * w.mode.tabwidth)
+            if w.buffer.usetabs:
+                # see HACK in buffer
+                w.insert_string_at_cursor('\t  \t')
+            else:
+                w.insert_string_at_cursor(' ' * w.mode.tabwidth)
             return
 
         # insert the correct amount of whitespace
-        ws  = w.buffer.count_leading_whitespace(y)
+        ws = w.buffer.count_leading_whitespace(y)
         if lvl != ws:
             w.delete(Point(0, y), Point(ws, y))
-            w.insert_string(Point(0, y), ' ' * lvl)
+            if w.buffer.usetabs:
+                nt = lvl // w.mode.tabwidth
+                ns = lvl % w.mode.tabwidth
+                s = ('\t  \t' * nt) + (' ' * ns)
+            else:
+                s = ' ' * lvl
+            w.insert_string(Point(0, y), s)
         x2 = max(x, lvl)
         if w.logical_cursor().x < x2:
             w.goto(Point(x2, y))
diff --git a/mode/__init__.py b/mode/__init__.py
index aa5ea23..17d11c1 100644
--- a/mode/__init__.py
+++ b/mode/__init__.py
@@ -1,5 +1,9 @@
+import math
+import os
+import string
+import sys
+import traceback
 from util import defaultdict
-import math, os, string
 import color, method
 from lex import Lexer
 from point import Point
@@ -458,8 +462,11 @@ class Fundamental(Handler):
         except Exception, e:
             if DEBUG:
                 raise
-            else:
-                self.window.set_error(str(e))
+            exc_type, exc_value, exc_traceback = sys.exc_info()
+            data = ''.join(traceback.format_tb(exc_traceback))
+            self.window.application.data_buffer("*Exception*", data,
+                                                switch_to=False)
+            self.window.set_error(str(e))
 
     def region_added(self, p, newlines):
         if self.lexer is not None:
diff --git a/mode/c.py b/mode/c.py
index ee6fff1..92a99e4 100644
--- a/mode/c.py
+++ b/mode/c.py
@@ -17,9 +17,10 @@ class ErrorGrammar(Grammar):
         PatternRule('continuation', r'\\\n$'),
     ]
 
-chr1 = '[a-zA-Z_]'
-chr2 = '[a-zA-Z0-9_]'
-word = chr1 + chr2 + '*'
+chr1   = '[a-zA-Z_]'
+chr2   = '[a-zA-Z0-9_]'
+word   = chr1 + chr2 + '*'
+spaces = r'[\t ]+'
 
 class MacroGrammar(Grammar):
     rules = [
@@ -36,7 +37,7 @@ class MacroGrammar(Grammar):
 
 class CGrammar(Grammar):
     rules = [
-        PatternRule('spaces', r' +'),
+        PatternRule('spaces', spaces),
 
         PatternMatchRule('x', r'(\()( *)(' + word + r')(\**)( *)(\))( *)(?=[a-zA-Z0-9_\(])',
                          'delimiter', 'spaces', 'c.type', 'c.operator',