A party to a child custody proceeding, including a modification proceeding, or a petitioner or respondent in a proceeding to enforce or register a child custody determination, is not subject to personal jurisdiction in this State for another proceeding or purpose solely by reason of having participated, or of having been physically present for the purpose of participating, in the proceeding. A person who is subject to personal jurisdiction in this State on a basis other than physical presence is not immune from service of process in this State. A party present in this State who is subject to the jurisdiction of another state is not immune from service of process allowable under the laws of that state. The immunity granted by subsection (a) of this section does not extend to civil litigation based on acts unrelated to the participation in a proceeding under this title committed by an individual while present in this State.