diff --git a/src/screen.c b/src/screen.c
index 45e7c7c..ee61a01 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -3649,13 +3649,19 @@
 		draw_state = WL_FOLD;
 		if (fdc > 0)
 		{
-		    /* Draw the 'foldcolumn'. */
-		    fill_foldcolumn(extra, wp, FALSE, lnum);
-		    n_extra = fdc;
-		    p_extra = extra;
-		    p_extra[n_extra] = NUL;
-		    c_extra = NUL;
-		    char_attr = hl_attr(HLF_FC);
+		    /* Draw the 'foldcolumn'.  Allocate a buffer, "extra" may
+		     * already be in used. */
+		    p_extra_free = alloc(12 + 1);
+
+		    if (p_extra_free != NULL)
+		    {
+			fill_foldcolumn(p_extra_free, wp, FALSE, lnum);
+			n_extra = fdc;
+			p_extra_free[n_extra] = NUL;
+			p_extra = p_extra_free;
+			c_extra = NUL;
+			char_attr = hl_attr(HLF_FC);
+		    }
 		}
 	    }
 #endif