diff --git a/rmacs/TODO b/rmacs/TODO
index be84b45..0698ae5 100644
--- a/rmacs/TODO
+++ b/rmacs/TODO
@@ -17,3 +17,7 @@ behaviour near the end of the demo file.
 
 Catch and handle SIGWINCH.
 See http://man7.org/tlpi/code/online/dist/tty/demo_SIGWINCH.c.html
+
+Cut-and-paste via X doesn't work too well. The trailing spaces on each
+line are part of the selection. Worth trying to elide them? Or fill
+unprinted slots with #f or #\nul?