It probably refers to
http://lists.suckless.org/dev/1211/13427.html
and does not seem like a bug in st.

Thanks "Eon S. Jeon" <esjeon@hyunmu.am>!

The bounding boxes for characters can be scaled using "cwscale" and "chscale"
to scale the width and height respectively.

To be more specific, now tty creation is delayed until X window is
actually mapped; last ConfigureNotify before mapping determines
initial tty size.
Please report problems if there are any.

Thanks Alexander Sedov <alex0player@gmail.com>!

This patch adds the keys for the keypad (in both modes, application mode or
ansi mode) and function keys. It uses the same convention than xterm and
instead of using the XK_Fxx values it generates them using F1-F12 and
modifiers. For example:

   F1 -> ^[OP
   F1 + Shift = F13 -> ^[[1;2P
   F1 + Control = F25 -> ^[[1;5P
   F1 + Mod2 = F37 -> ^[[1;6P
   F1 + Mod1 = F49 -> ^[[1;3P
   F1 + Mod3 = F61 -> ^[[1;4P

It is also important notice than the terminfo capability kIC (shifted insert
key) only can be generated using the keypad keyboard, because the shorcut
for selection paste is using the same combination.

After this path the number of elements in the Key array becomes high, and
maybe a sequencial search is not enough efficient now.
---
 TODO         |    6 +---
 config.def.h |  102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 st.info      |   70 ++++++++++++++++++++++++++++++++++++++--
 3 files changed, 169 insertions(+), 9 deletions(-)

The main loop waits until there is some data to read in file descriptors of
the X server or the pseudo tty. But it uses a timeout in select(), which
causes that st awake each 20 ms, even it doesn't have something to do. This
patch removes this problem removing the timeout, which is not needed.
---
 TODO |    1 -
 st.c |   27 +++------------------------
 2 files changed, 3 insertions(+), 25 deletions(-)