This works for me:
Shoes.app do
mystack = stack :width => 50, :height => 50 do
background red
hover do
mystack.clear {background blue}
end
leave do
mystack.clear {background red}
end
end
endIs this what you wanted to do? The only thing I changed was putting the stack in a variable and using thisVariable.clear instead of just clear. Concerning the multiple Windows, I think I have read somewhere that Shoes can do this, but I haven't used this functionality yet, so I can't help with that.
