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
gd.verticalAlignment= GridData.FILL;
		gd.grabExcessVerticalSpace= true;
		gd.horizontalSpan= 1;
		buttons.setLayoutData(gd);
		
		return new Control[] { label, list, buttons };
	}
	/*
	 * @see DialogField#getNumberOfControls
	 */	
	public int getNumberOfControls() {
		return 3;	
	}
	/**
	 * Sets the minimal width of the buttons. Must be called after widget creation.
	 */		
	public void setButtonsMinWidth(int minWidth) {
		if (fLastSeparator != null) {
			((GridData)fLastSeparator.getLayoutData()).widthHint= minWidth;
		}
	}
	
	
	
	
	/**
	 * Returns the list control. When called the first time, the control will be created.
	 * @param The parent composite when called the first time, or <code>null</code>
	 * after.
	 */