Bug 293130 Polishing the Filter extension point
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/ResourceFilterGroup.java
Object arguments = null;
	String id = null;
	IPath path = null;
	IProject project = null;
	int type = 0;
	FilterCopy parent = null;
	LinkedList children = null;
	UIResourceFilterDescription original = null;
	int serialNumber = ++lastSerialNumber;
	static private int lastSerialNumber = 0;
	public FilterCopy(UIResourceFilterDescription filter) {
		internalCopy(filter);
		original = filter;
	}
	public void setParent(FilterCopy parent) {
		this.parent = parent;
	}
	public boolean canAcceptDrop() {
		int limit = getChildrenLimit();
		if (limit > 0) {
			FilterCopy[] tmp = getChildren();
			return (tmp == null) || (tmp.length < limit);
		}
		return false;