It has long been accepted that a court of equity, acting in personam, can enjoin one over whom it has jurisdiction from bringing an action in a foreign tribunal. A nice question is presented when an effort is made to determine on what occasions the court will exercise that power. It is frequently said that it will be exercised but sparingly, and then only where a clear equitable right is established by the petitioner. This, in spite of the strong language commonly accompanying such statements, is no more than that which the court requires for the issuance of any injunctional decree. The same equitable principles upon which is based the issuance of an injunction elsewhere in actions in chancery are equally controlling here.