Bug 27491 Cannot add classpath variable to project
build id : 200212020010 The buttons OK and extend... are always disabled in the add variable dialog
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/dialogfields/ListDialogField.java
/*
	 * @see DialogField#doFillIntoGrid
	 */
	public Control[] doFillIntoGrid(Composite parent, int nColumns) {
		PixelConverter converter= new PixelConverter(parent);
		
		assertEnoughColumns(nColumns);
		
		Label label= getLabelControl(parent);
		GridData gd= gridDataForLabel(1);
		gd.verticalAlignment= GridData.BEGINNING;
		label.setLayoutData(gd);
		
		Control list= getListControl(parent);
		gd= new GridData();
		gd.horizontalAlignment= GridData.FILL;
		gd.grabExcessHorizontalSpace= false;
		gd.verticalAlignment= GridData.FILL;
		gd.grabExcessVerticalSpace= true;
		gd.horizontalSpan= nColumns - 2;
		gd.widthHint= converter.convertWidthInCharsToPixels(50);
		gd.heightHint= converter.convertHeightInCharsToPixels(6);
		list.setLayoutData(gd);
		
		Composite buttons= getButtonBox(parent);
		gd= new GridData();
		gd.horizontalAlignment= GridData.FILL;
		gd.grabExcessHorizontalSpace= false;