Composite comp = new Composite(shell, SWT.NONE);
comp.setLayout(new GridLayout(4, false));
Label hidenLabel = new Label (comp, SWT.NONE);
GridData gridData = new GridData(SWT.FILL, SWT.FILL, true, true);
hidenLabel.setGridData(gridData );
//hide the button
gridData .exclude = true;
comp.pack();