(describe-char-padded-string): Compose with TAB

only if there's a font for CH.
(describe-char): Fix the condition for detecting a trivial
composition.

lisp/ChangeLog

+2009-11-19  Kenichi Handa  <handa@m17n.org>
+
+	* descr-text.el (describe-char-padded-string): Compose with TAB
+	only if there's a font for CH.
+	(describe-char): Fix the condition for detecting a trivial
+	composition.
+
 2009-11-18  Alan Mackenzie  <acm@muc.de>
 
 	* progmodes/cc-menus.el (cc-imenu-java-generic-expression): A new,

lisp/descr-text.el

@@ -353,7 +353,9 @@ This function is semi-obsolete.  Use `get-char-code-property'."
 ;; Return a string of CH with composition for padding on both sides.
 ;; It is displayed without overlapping with the left/right columns.
 (defsubst describe-char-padded-string (ch)
-  (compose-string (string ch) 0 1 (format "\t%c\t" ch)))
+  (if (internal-char-font nil ch)
+      (compose-string (string ch) 0 1 (format "\t%c\t" ch))
+    (string ch)))
 
 ;; Return a nicely formated list of categories; extended category
 ;; description is added to the category name as a tooltip
@@ -446,7 +448,8 @@ as well as widgets, buttons, overlays, and text properties."
 				(setq glyph (lgstring-glyph components j))
 				(= (lglyph-from glyph) glyph-from))
 		      (setq j (1+ j)))
-		    (if (and (= i (1- j))
+		    (if (and (= to (1+ from))
+			     (= i (1- j))
 			     (setq glyph (lgstring-glyph components i))
 			     (= char (lglyph-char glyph)))
 			;; The composition is trivial.