Setting Menubar Width

[Len Morgan]

I'm trying to set a menu bar on my main stack that I want to run the 
entire width of the stack but I can't seem to get it to DISPLAY any 
wider that the buttons themselves.  I can see the sizing handles are 
stretched across the stack but the background color is showing through.  
Short of putting up a rectangle the same color as the menubar (which is 
different than the background color of the stack, is there anyway to 
stretch out the menubar?

TIA,

Len Morgan