Dear LilyPond users,
I must admit I don't always understand the \tweak command, but I use it often to reposition objects here and there. As I understand it, it doesn't seem to work on markup objects attached to whole-bar rests. I have attached a tiny example below. The workaround is easy of course: just use \once \override MultiMeasureRestText #'extra-offset, but I thought I would mention it just in case it's a bug, or perhaps I misunderstood the \tweak command.
\version "2.16.1"
\relative c {
R1-\tweak #'extra-offset #'(-9 . -9) _"I"
}
Regards,
Kevin Barry