diff --git a/src/textformat.c b/src/textformat.c
index a1a3e16..5a52950 100644
--- a/src/textformat.c
+++ b/src/textformat.c
@@ -795,7 +795,7 @@
 	// The width is the window width minus 'wrapmargin' minus all the
 	// things that add to the margin.
 	textwidth = curwin->w_width - curbuf->b_p_wm;
-	if (cmdwin_type != 0)
+	if (curbuf == cmdwin_buf)
 	    textwidth -= 1;
 #ifdef FEAT_FOLDING
 	textwidth -= curwin->w_p_fdc;