if(! child.isDisposed()){
    child.dispose();
 }
 paramComposite.layout(true, true);

if(child.getLayoutData() instanceof GridData){
    ((GridData)child.getLayoutData() ).exclude = true;
 }
 paramComposite.layout(true, true);

Composite newChild = new Composite(paramComposite , SWT.NON)
 paramComposite.layout(true, true);

existingControl.setParent(paramComposite );
 existingControl.setLayoutData(existingControlLayoutData);
 paramComposite.layout(true, true);