diff --git a/src/evalfunc.c b/src/evalfunc.c
index 2bbdefc..7c781d8 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -11841,8 +11841,8 @@
 	    if ((syntax_flags & HL_CONCEAL) && curwin->w_p_cole < 3)
 	    {
 		cchar = syn_get_sub_char();
-		if (cchar == NUL && curwin->w_p_cole == 1 && lcs_conceal != NUL)
-		    cchar = lcs_conceal;
+		if (cchar == NUL && curwin->w_p_cole == 1)
+		    cchar = (lcs_conceal == NUL) ? ' ' : lcs_conceal;
 		if (cchar != NUL)
 		{
 # ifdef FEAT_MBYTE