The LinkSubmit component does not submit the form, when (the default) Prototype library is used. It works fine with jQuery.
The "submit" event and then "prepareForSubmit" are emitted, but then I lost track of the event chain.
Workaround: Switch to jQuery.
Tested on Tapestry 5.4.3 and 5.4.2 / Oracle JDK 1.8.0_181