magics only complete from line start if w/o % prefix

IPython/completer.py

@@ -433,7 +433,9 b' class IPCompleter(Completer):'
         else:
             matches = self.global_matches(text)
             # this is so completion finds magics when automagic is on:
-            if matches == [] and not text.startswith(os.sep):
+            if (matches == [] and 
+                 not text.startswith(os.sep) and
+                 not ' ' in self.lbuf):
                 matches = self.attr_matches(self.magic_prefix+text)
         return matches