I created an add-in similar to how it is described above. Mostly following PMRoz' description, with Mewing's tip at the end for the correct customization setting.
My add-in is a toolbar, a single clickable icon. When it is installed by clicking on the .jmpaddin file, it gets installed ok, but the toolbar is not enabled by default. The user needs to go in to view->toolbars and enable it manually. Is there way to force it to be enabled? I have autoload=1 in the .def file. I have no idea what other setting might be able to force this.
Figured I give it one more shot... When making a custom toolbar add-in, does anyone know how to make the toolbar enabled by default when a user installs the add-in? For my add-in it seems to be a coin toss whether users see it enabled by default or have to go in through the view->toolbar menu to enable it.