hsdev: Coloring errors

Right now I foun 3 small errors:

-- problem1 is not colored as function wherever @ is used
problem1 t@(x,y) = x 

-- let is not colored when in one line"
problem2 = do
   let x = 1
   print x

-- below comment is not colored
data Problem3 = P {
      fun1 :: Int,
      -- fun2 :: Int,
      fun3 :: Int,
   }   

also I think when should be colored (as until is)

Thanks!