Fixed output for last character-finding function

source/libublsettings.c

@@ -335,6 +335,7 @@ int yon_char_find_last(char *source, char find){
     int size = strlen(source);
     int i=size;
     for (;source[i]!=find&&i>0;i--);
+    if (source[i]!=find)i=-1;
     return i;
 }