Moving here from a downstream bug report:
https://bugzilla.redhat.com/show_bug.cgi?id=606169

Description of problem:
In Evo Preferences, 'Calendar and Tasks', General tab, tick all boxes from Mon
to Sun for 'Work days'. In Evo calendar, click on 'Work week' view, see seven
days (Mon to Sun) showing OK. Close Evo.

Start Evo again, go to calendar view, select 'Work Week' view, only see Mon to
Fri (NO Sat or Sun). Open Evo Preferences, and see that Sat and Sun are still
ticked for workweek view. Untick Sun, see that calendar now changes to show
Mon-Sat (as Sat is still ticked). Re-tick Sun, and calendar changes to show
Mon-Sun.

Note - after ticking all days Mon-Sun in Preferences, gconf-editor
/apps/evolution/calendar/display/working_days = 127 after closing Evo. When Evo
starts again and only shows Mon-Fri in 'Work Week' view,
/apps/evolution/calendar/display/working_days is still 127 (ie. no change)

Version-Release number of selected component (if applicable):
Name       : evolution
Arch       : x86_64
Version    : 2.30.1
Release    : 8.fc13

Name       : evolution-exchange
Arch       : x86_64
Version    : 2.30.1
Release    : 3.fc13

How reproducible:
Always

Actual results:
Only see Mon-Fri.

Expected results:
See Mon-Sun on Evo startup when all day boxes are tick in Evo prefs.