Bug 255172 [Import/Export] Warning message in the import wizard is not so helpful
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/wizards/datatransfer/WizardProjectsImportPage.java
public void checkStateChanged(CheckStateChangedEvent event) {
				setPageComplete(projectsList.getCheckedElements().length > 0);
			}
		});
		projectsList.setInput(this);
		projectsList.setComparator(new ViewerComparator());
		createSelectionButtons(listComposite);
	}
	/**
	 * Create the selection buttons in the listComposite.
	 * 
	 * @param listComposite
	 */
	private void createSelectionButtons(Composite listComposite) {
		Composite buttonsComposite = new Composite(listComposite, SWT.NONE);
		GridLayout layout = new GridLayout();
		layout.marginWidth = 0;
		layout.marginHeight = 0;
		buttonsComposite.setLayout(layout);
		buttonsComposite.setLayoutData(new GridData(
				GridData.VERTICAL_ALIGN_BEGINNING));
		Button selectAll = new Button(buttonsComposite, SWT.PUSH);
		selectAll.setText(DataTransferMessages.DataTransfer_selectAll);
		selectAll.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent e) {
				projectsList.setCheckedElements(selectedProjects);
				setPageComplete(projectsList.getCheckedElements().length > 0);
			}
		});
		Dialog.applyDialogFont(selectAll);