A customer reported the following bug trace:
<verbatim>
> can't read "data(1,width)": no such element in array
>     while executing
> "expr {$xd + $data($page,width)}"
>     (procedure "_draw_page" line 15)
>     invoked from within
> "_draw_page $path $page 0"
>     (procedure "NoteBook::_redraw" line 10)
>     invoked from within
> "NoteBook::_redraw $path"
>     (procedure "NoteBook::_resize" line 13)
>     invoked from within
> "NoteBook::_resize .fm.frame.ft.p.fa.n"
>     (command bound to event)
> --Traceback--
> INNER:invokeStk1 .fm.frame.ft.p.fp.t.hdr.t.f.c3 create image 0 1 -anchor nw -image lightLineDn.fm.frame.ft.p.fp.t.hdr.t.f.c3 -tags lightLineDn
> CALL:createArrows .fm.frame.ft.p.fp.t.hdr.t.f.c3 7 4 flat
</verbatim>

IMHO the _Resize event got in before initialisation got completed.
A test patch is in a branch with the id of this ticket (not jet assigned)