I'm trying to use the multi select rows function of DataTables, for now that make the job but when i add a
"defaultContent": "<button class='btn_planning'>Show</button>"
The easiest would be to turn off the selector for the specific column holding a <button> :
selector: 'td:not(:nth-child( COLUMN_INDEX ))' //dataTable column index + 1
see demo -> http://jsfiddle.net/f8ke0wwk/