Hide subgrid with serach box in Javascript

Hi, I have add a subgrid in the case entity and when I hide it, I'm facing two poblems.

1. I can't hide the search box. I try to get its id with the developer tools but cant hide it using the same code I use for hide the subgrid. If in the grid properties I disable the 'Display Search Box' check, it is visible a lines forming the rectangle.

Image may be NSFW.
Clik here to view.

2. After hide it and see the search box or the lines, in both cases there a blank space used by the grid. As show in this picture.

Image may be NSFW.
Clik here to view.

Any ideas on how to resolve this?

This is my code:

function hide_grid(){

 var grid = document.getElementById("subgridkbarticles"); 
    if (grid == null) { //make sure the grid has loaded 
        setTimeout(function () { hide_grid(); }, 2000);
        return;
    }

grid.control.setVisible(false);

}

Thanks!