Basically, I have an eclipse Composite which contains a label and then some
other components. I need to change the size of the label and then repack the
container to reflect this change.

Here is where the Composite debugView, which contains the label, is initialized.
Java Code:
public void createPartControl(Composite parent) {
  //....some code here
  parent.setLayout(new GridLayout(1, false));
  mainView = new Composite(parent, SWT.NONE);
  debugView = new Composite(parent, SWT.BORDER);
//...some more code
Here, the label is initialized.
Java Code:
GridLayout layout = new GridLayout(1, false);
layout.marginLeft = 1;
layout.marginTop = 1;
layout.marginRight = 1;
layout.marginBottom = 1;
// Create the debug view
debugLabel = new Label(debugView, SWT.BORDER|SWT.WRAP);
Here, the label size is changed and the debugView displayed.
Java Code:
Basically, I want the debugView to now contain a debugLabel which is of the
size i specified. It isn't, because debugView.pack() sets the label size to
its preferred size. However, if I don't pack everything the debugLabel will
cover some of the component which lies below it. So, I want to repack everything but keep the size of the label I specified.