FormNode.getHandle() implements an hack to avoid restoring the
original node after IDE restarts (see commens in the code, reported below)

    // ----------
    // Persistence hacks - for the case the node is selected in some
    // (standalone) properties window when IDE exits. We don't restore the
    // original node after IDE restarts (would require to load the form), but
    // provide a fake node which destroys itself immediately - closing the
    // properties window. [Would be nice to find some better solution...]

This can be avoided returning null to signal that the node is not persistable, see javadoc of Node.getHandle() (reported below):

"
public abstract Node.Handle getHandle()
    
Obtain handle for this node (for serialization). The handle can be serialized   and Node.Handle.getNode() used after deserialization to obtain the original node.
Returns:
    the handle, or null if this node is not persistable
"