diff --git a/buffer.py b/buffer.py
index c08c71b..5da8ff4 100644
--- a/buffer.py
+++ b/buffer.py
@@ -152,12 +152,10 @@ class Buffer(object):
         if w in self.windows:
             self.windows.remove(w)
             modename = w.mode.name()
-            found = False
-            for w2 in self.windows:
-                if w2.mode.name() == modename:
-                    found = True
-                    break
-            if not found:
+            if modename in self.highlights:
+                for w2 in self.windows:
+                    if w2.mode.name() == modename:
+                        return
                 del self.highlights[modename]
     def _region_add(self, p1, p2, lines, act):
         move = DelMove(self, p1, p2)
diff --git a/mode/c.py b/mode/c.py
index 6259543..4b4ec70 100644
--- a/mode/c.py
+++ b/mode/c.py
@@ -205,7 +205,7 @@ class CMake(method.shell.Exec):
 
 class C(mode.Fundamental):
     modename    = 'C'
-    extensions  = ['.c']
+    extensions  = ['.c', '.h', '.cpp']
     tabbercls   = CTabber
     grammar     = CGrammar
     opentokens  = ('delimiter',)