--- a/ag.el	Wed Mar 01 16:15:48 2017 +0200
+++ b/ag.el	Thu Mar 02 22:41:44 2017 +0200
@@ -41,7 +41,7 @@
   "Face for line number.")
 
 (defvar my/ag-keywords
-  '(("[1-9][0-9]\\{0,5\\}:" . (0 'my/ag-lineno-face))
+  '(("^[1-9][0-9]\\{0,5\\}:" . (0 'my/ag-lineno-face))
     ("^[^:]\\{6\\}.*" . (0 'my/ag-path-face))))
 
 (defun my/ag-font-lock-extend-region ()
@@ -87,15 +87,13 @@
      :command (list "ag" "--group" "--nocolor" regex))))
 
 (defun my/ag-project-root ()
-  (let ( (backend (vc-responsible-backend default-directory)) )
-    (if backend
-        (condition-case err
+  (condition-case err
+      (let ( backend )
+        (setq backend (vc-responsible-backend default-directory))
+        (if backend
             (vc-call-backend backend 'root default-directory)
-          (vc-not-supported
-           (unless (eq (cadr err) 'root)
-             (signal (car err) (cdr err)))
-           nil))
-      default-directory)))
+          default-directory))
+    (error default-directory)))
 
 ;;;###autoload
 (defun my/ag (regex)