patch 8.2.2640: screenstring() returns non-existing composing characters Commit: https://github.com/vim/vim/commit/f1387285e2ebe5cb3688d729fc6fd01a169a76c1 Author: Bram Moolenaar <Bram@vim.org> Date: Mon Mar 22 17:11:15 2021 +0100 patch 8.2.2640: screenstring() returns non-existing composing characters Problem: screenstring() returns non-existing composing characters. Solution: Only use composing characters if there is a base character.

--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -7902,7 +7902,7 @@ f_screenstring(typval_T *argvars, typval
 	c = ScreenLines[off];
     buflen += mb_char2bytes(c, buf);
 
-    if (enc_utf8)
+    if (enc_utf8 && ScreenLinesUC[off] != 0)
 	for (i = 0; i < Screen_mco && ScreenLinesC[i][off] != 0; ++i)
 	    buflen += mb_char2bytes(ScreenLinesC[i][off], buf + buflen);