KeyCancellation cause

[Jean Abou Samra]

Hi,

Please have a look at the output of

\version "2.23.4"

{
  \key cis \major
  s1
  \tweak font-size -3 \key b \major
  s1
  \footnote #'(-2 . 2) "key signature" \key d \major
  s1
}

The KeyCancellation's cause is the key event, not
the KeySignature grob. One effect is that a direct
\tweak affects both grobs. Another is that things
like footnote marks go on both grobs. Yet another
is that both KeySignature and KeyCancellation have
point-and-click pointing to the \key invocation in
the source.

Usually, only one grob is caused by an event. The
other grobs that could be traced back to that event
are marked as caused by that grob. For instance,
Accidental grobs are caused by NoteHead grobs,
Stem grobs likewise.

Okay to make KeySignature cause of KeyCancellation?

Regards,
Jean