Staff properties apply button doesn't work

Steps to reproduce bug
1. Open or create a new score
2. Right click on an empty part of the staff and choose "Staff Properties"
3. Make changes to the staff properties such as InstrumentLong, InstrumentShort, number of staff lines
4. Press "Apply" to preview changes

Expected behavior: Changes should appear on score

Actual behavior: Changes do not appear until after you click "OK"

MuseScore version: r. 2517

(Operating System: Windows XP)

first reported by Xavierjazz: http://www.musescore.org/en/node/3954