Fix speedbar highlighting bug.

* lisp/speedbar.el (speedbar-unhighlight-one-tag-line): Avoid
unhighlighting due to frame switching.

Fixes: debbugs:10275

lisp/ChangeLog

+2012-03-10  Martin Rudalics  <rudalics@gmx.at>
+
+	* speedbar.el (speedbar-unhighlight-one-tag-line): Avoid
+	unhighlighting due to frame switching (Bug#10275).
+
 2012-03-10  Chong Yidong  <cyd@gnu.org>
 
 	* minibuffer.el (completion-in-region, completion-help-at-point):

lisp/speedbar.el

@@ -3987,11 +3987,11 @@ TEXT is the buffer's name, TOKEN and INDENT are unused."
 
 (defun speedbar-unhighlight-one-tag-line ()
   "Unhighlight the currently highlighted line."
-  (if speedbar-highlight-one-tag-line
-      (progn
+  (when (and speedbar-highlight-one-tag-line
+	     (not (eq this-command 'handle-switch-frame)))
     (speedbar-delete-overlay speedbar-highlight-one-tag-line)
-	(setq speedbar-highlight-one-tag-line nil)))
-  (remove-hook 'pre-command-hook 'speedbar-unhighlight-one-tag-line))
+    (setq speedbar-highlight-one-tag-line nil)
+    (remove-hook 'pre-command-hook 'speedbar-unhighlight-one-tag-line)))
 
 (defun speedbar-recenter-to-top ()
   "Recenter the current buffer so point is on the top of the window."