button woes

[jverzani]

To make a button with a callback utilizes a pattern like

b = button("click me")
window(b)
map(b) do args...
   println("clicked me")
end

All good, but if things get more complicated, the button fails to be lifted:

window(toolbar(b), grow(b))

Now clicking on b does not update the GUI (any of the three instances)

Also directly pushing a value doesn't work, though this will at first:

push!(b.signal, nothing)

Not sure what happens here...