If the area you've marked out contains more squares than the total number of squares that make up the tetris piece symbols then it is wrong. If you were to mark out an area containing all four of those symbols the area should take up eight squares.
In regards to the black and white squares, do some testing to see whats shown as a valid input when trying to group different numbers of them together.
You've made a faulty assumption about how blocks interact with other elements
The only thing blocks care about are the borders (line and edge of puzzle). Your line is outlining more than 8 squares, the black and white squares do not count as a border.
I've input the solution that includes all four blocks, but takes up only 8 squares (both columns) several times, but also separated the colors; that was the first thing I did. It didn't work, so I thought there was more to it. Arg.
I'll go do something different for a while. Thanks.