@Override
	public void createPartControl(Composite parent) {
		
//Create Form and Toolkit
		managedForm = new ManagedForm(parent);
		form = managedForm.getForm();
		toolkit = managedForm.getToolkit();
		form.setText("Function Edit Form - ");
		
		//Set layout
		ColumnLayout formLayout = new ColumnLayout();
		form.getBody().setLayout(formLayout);
		
		//Add the tabFolder
		tabFolder = new CTabFolder(form.getBody(), SWT.FLAT | SWT.BOTTOM);
		toolkit.adapt(tabFolder, true, true);
		ColumnLayoutData clData = new ColumnLayoutData(ColumnLayoutData.FILL);
		clData.heightHint = 0;
		tabFolder.setLayout(new ColumnLayout());
		tabFolder.setLayoutData(clData);
		Color selectedColor = toolkit.getColors().getColor(FormColors.SEPARATOR);
		tabFolder.setSelectionBackground(new Color[] {selectedColor, toolkit.getColors().getBackground()}, new int[] {100});
		toolkit.paintBordersFor(tabFolder);
		tabFolder.setCursor(FormsResources.getHandCursor());
		tabFolder.setSimple(false);
		
		//Create the Function Tab and contents
		final CTabItem item = new CTabItem(tabFolder, SWT.NULL);
		item.setText("Function");
		functionTabContent = toolkit.createComposite(tabFolder);//form.getBody());
		item.setControl(functionTabContent);
		clData = new ColumnLayoutData(ColumnLayoutData.FILL);
		functionTabContent.setLayoutData(clData);
		functionTabContent.setLayout(new ColumnLayout());

... Adding things to the Composite functionTabContent...

form.getForm().layout(true, true);
}

		tabFolder.setLayout(new ColumnLayout());
		tabFolder.setLayoutData(clData);