Another posting for the ‘comparative conflicts /dispute resolution’ binder. In order not to be found to have voluntary appeared (‘submitted to jurisdiction’), civil procedure rules worldwide require defendants to flag their opposition to jurisdiction early on in the proceedings. Indeed at the threshold of the litigation: in limine litis.
In EU law, the Court of Justice ruled in Elefanten Schuh that where civil procedure of the Member States requires a defence on the merits at the very earliest opportunity, such defence does not jeopardise objection to jurisdiction made at the same occasion. (Case-law now reflected in the wording of the Brussels I Regulation and its Recast successor).
There is as yet however no CJEU case-law on what level of interaction with the courts leads to submission.
In England, Zumaz Nigeria v First City  EWCA Civ 567 recently held that application for disclosure does not entail submission: for one may need those very documents to contest jurisdiction.
Thank you RPC for now flagging Shenzhen CTS International Logistics Co Ltd v Dajiang International Investment Co Ltd. The court found that by applying to strike out the claim and seeking security for costs (to include the period after the hearing of the stay application), defendant had invoked the jurisdiction of the Hong Kong courts. As always of course the decision was based on factual merit which RPC’s David Smyth and Hannah Fletcher summarise very well in the posting hyperlinked above.
Beware before you engage with the courts, if you do not wish to be seen as having submitted.
(Handbook of) European Private international law, 2nd ed. 2016, Chapter 2, Heading 2.2.7.