What is the "strong reason" for not imposing an anti-suit injunction on contractual grounds?

This “strong reason” test for not imposing an anti-suit injunction on contractual grounds, is analogous to the “strong cause” test applied by Canadian and English courts in exercising their discretion to grant or decline a stay of domestic proceedings to enforce a forum selection clause. The “strong cause” test for a stay of proceedings was applied in Z.I. Pompey Industrie v. ECU‑Line N.V., 2003 SCC 27 at paras. 1, 19–21. It provides that where parties are bound by a valid forum selection clause in favour of a foreign jurisdiction, a court must grant a stay of the domestic proceeding unless the plaintiff can show sufficiently strong reasons to support the conclusion that it would not be reasonable or just in all of the circumstances to require the plaintiff to adhere to the terms of the forum selection clause: Z.I. Pompey at para. 39.