diff --git a/src/hardcopy.c b/src/hardcopy.c
index e2e5211..dd1f2e0 100644
--- a/src/hardcopy.c
+++ b/src/hardcopy.c
@@ -293,6 +293,7 @@
     pattr->italic = (highlight_has_attr(hl_id, HL_ITALIC, modec) != NULL);
     pattr->underline = (highlight_has_attr(hl_id, HL_UNDERLINE, modec) != NULL);
     pattr->undercurl = (highlight_has_attr(hl_id, HL_UNDERCURL, modec) != NULL);
+    // TODO: HL_UNDERDOUBLE, HL_UNDERDOTTED, HL_UNDERDASHED
 
 # if defined(FEAT_GUI) || defined(FEAT_TERMGUICOLORS)
     if (USE_24BIT)