System bar line and measure number do not follow staff spacer up

Context:: commit 4ee8a2e44 (self-compiled, Qt SDK, Ubuntu 11.10)

Steps:
1) Create a score with system bar lines (for instance with more than one instrument) and measure numbers at start of system (the default)
2) Add a "Staff Spacer Up" to some measure of the TOP staf

Result: the system bar line and the measure number do not follow the top staff shift and become disjoined from it (2nd system of example below):

Notes:
A sample score is attached.

This does not happen with up spacers applied to non-top staves (3rd system of example above).