Bug 42767 Grabbing vertically on add constructor/ gen contructors using fields action
The source actions related to creating constructors is not relayouting properly on resize. The lowermost checkbox is grabbing vertically when it shouldn't be. In the case of the gen. constructors using fields dialog, the upper combobox and label are grabbing vertical space when they shouldn't be either.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/AddUnimplementedConstructorsAction.java
* Method declared on SelectionDispatchAction
	 */
	public void selectionChanged(IStructuredSelection selection) {
		try {
			setEnabled(canEnable(selection));
		} catch (JavaModelException e) {
			
			if (JavaModelUtil.filterNotPresentException(e))
				JavaPlugin.log(e);
			setEnabled(false);
		}
	}
	
	private boolean canEnable(IStructuredSelection selection) throws JavaModelException {
		if ((selection.size() == 1) && (selection.getFirstElement() instanceof IType)) {
			IType type= (IType) selection.getFirstElement();
			return type.getCompilationUnit() != null && type.isClass(); 
		}
		if ((selection.size() == 1) && (selection.getFirstElement() instanceof ICompilationUnit))
			return true;
		return false;
	}
	
	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction
	 */
	public void run(IStructuredSelection selection) {
		Shell shell= getShell();
		try {
			IType type= getSelectedType(selection);