diff --git a/src/xdisp.c b/src/xdisp.c
index c1a2b6003d5..7903ba582a4 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -6410,13 +6410,12 @@ handle_single_display_spec (struct it *it, Lisp_Object spec, Lisp_Object object,
 	      && (tem = XCDR (tem), CONSP (tem))
 	      && (tem = XCAR (tem), !NILP (tem)))
 	    {
-	      if (FIXNUMP (tem) && XFIXNUM (tem) >= 0)
+	      if (FIXNATP (tem))
 		margin_column = (int) XFIXNUM (tem);
 	      else if (SYMBOLP (tem))
 		{
-		  Lisp_Object columns_list = Fsymbol_value
-		    (EQ (location, Qleft_margin)
-		     ? Qleft_margin_columns : Qright_margin_columns);
+		  Lisp_Object columns_list = EQ (location, Qleft_margin)
+		    ? Vleft_margin_columns : Vright_margin_columns;
 		  int pos = 0;
 		  for (Lisp_Object tail = columns_list; CONSP (tail);
 		       tail = XCDR (tail), pos++)
@@ -39015,7 +39014,6 @@ The recommended non-zero value is between 100000 and 1000000,
 depending on your patience and the speed of your system.  */);
   max_redisplay_ticks = 0;
 
-  DEFSYM (Qleft_margin_columns, "left-margin-columns");
   DEFVAR_LISP ("left-margin-columns", Vleft_margin_columns,
     doc: /* List of symbols for left margin columns.
 Each symbol represents a mode that displays indicators in the left margin.
@@ -39027,8 +39025,9 @@ flymake indicators appear in column 0, outline in column 1, and hideshow
 in column 2.  Modes can use their symbol in a display spec like
 ((margin left-margin flymake) \">\") instead of a numeric column.  */);
   Vleft_margin_columns = Qnil;
+  DEFSYM (Qleft_margin_columns, "left-margin-columns");
+  Fmake_variable_buffer_local (Qleft_margin_columns);
 
-  DEFSYM (Qright_margin_columns, "right-margin-columns");
   DEFVAR_LISP ("right-margin-columns", Vright_margin_columns,
     doc: /* List of symbols for right margin columns.
 Each symbol represents a mode that displays indicators in the right margin.
@@ -39037,6 +39036,8 @@ where that mode's margin indicators appear.
 
 See `left-margin-columns' for more details.  */);
   Vright_margin_columns = Qnil;
+  DEFSYM (Qright_margin_columns, "right-margin-columns");
+  Fmake_variable_buffer_local (Qright_margin_columns);
 
   /* Called by decode_mode_spec.  */
   DEFSYM (Qfile_remote_p, "file-remote-p");