Fixed width xfce4-panel

[Aphyr]

Hello,

I used to be able to set a fixed width for the task list in xfce4-panel, 
which kept the panel size reasonably stable. Then I upgraded to 4.6.0, 
and I can set a minimum, but not a maximum, width. Is there any way to 
get my fixed-width panels back?

Rationale: I run OpenBox, and need some area of the desktop visible for 
workspace warping and getting the right-click menu. I typically use a 
fixed-width centered bottom panel with some area left open at both 
sides. Without fixed-width panels, I lose that space if there are many 
(6) windows onscreen--and the panel changes width every time I switch 
workspaces.

Any help would be much appreciated! Thanks,

--Aphyr