Bug 5677 Hierarchy outline has empty space
I opened a hierarchy view on IActionDelegate. Selected a few of the subinterfaces, changed the expansion state of the tree. Then, no matter which item I selected in the top window (the hierarchy tree), the bottom window (the outline table) always had exactly four empty rows before the first item was listed.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/dialogfields/ListDialogField.java
if (index == fRemoveButtonIndex) {
			return !sel.isEmpty();
		} else if (index == fUpButtonIndex) {
			return !sel.isEmpty() && canMoveUp();
		} else if (index == fDownButtonIndex) {
			return !sel.isEmpty() && canMoveDown();
		}
		return true;
	}		
	/*
	 * @see DialogField#updateEnableState
	 */ 	
	protected void updateEnableState() {
		super.updateEnableState();
		
		boolean enabled= isEnabled();
		if (isOkToUse(fTableControl)) {
			if (!enabled) {
				fSelectionWhenEnabled= fTable.getSelection();
				selectElements(null);
			} else {
				selectElements(fSelectionWhenEnabled);
				fSelectionWhenEnabled= null;
			}
			fTableControl.setEnabled(enabled);
		}
		updateButtonState();
	}
	/**
	 * Sets a button enabled or disabled.