diff --git a/src/popupwin.c b/src/popupwin.c
index 8cdb68a..6402ba3 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -2999,7 +2999,7 @@
 
     // Convert the number to a string, so that the function can use:
     //	    if a:c == "\<F2>"
-    buf[special_to_buf(c, mod_mask, TRUE, buf)] = NUL;
+    buf[special_to_buf(c, mod_mask, FALSE, buf)] = NUL;
     argv[1].v_type = VAR_STRING;
     argv[1].vval.v_string = vim_strsave(buf);