Remove header without buttons

Hi

Im using the following code which is provided by Dennis

Now I need to remove the boarder of the tree and when I use the property showHeader:false the buttons

are omitted from the tree ,I need to remove  the border and the expand and collapse tree button

and the buttons hello1 & 2 will remain on top of the screen.

JS Bin - Collaborative JavaScript Debugging

There is a way also to put the hello buttons in place the expand and collapse buttons( in the right side instead the left) but this is less important.

Thanks,

Stephane