Okay, silly me: I don’t know how I didn’t find this on search the first time I tried: http://www.smartmenus.org/forums/topic/main-menu-closes-on-mouse-out-even-when-showhideonclick-is-set-to-true
This achieves what I wanted.
However, I do want to make a comment on why somebody would want this. Specifically, I refer to this:
However, currently when showOnClick is set to true, the menu tree behaves like desktop menus – i.e. a click activates the main menu items and after that their sub menus appear immediately on hover. The idea is that this makes sense for someone who wants to use the script for some kind of app that mimics desktop apps.
The thing is that website menus are not necessarily the same as desktop menus. In the case of desktop menus, each parent link almost invariably has a sub-menu. Therefore, hovering horizontally leads to a seamless opening and closing of sub-menus.
In the case of many website menus, not every parent link has a sub-menu. For example, on the website that I’m working on, two menu items will have sub-menus, while the other five will not. The hybrid click/hover approach that works well on desktop menus doesn’t work so well in this context.
When I tested out my menu on a couple of non-developer friends, they found the menu troublesome – they felt that the sub-menus were arbitrarily appearing and disappearing. They didn’t feel that the website menu was behaving the same way as a desktop menu: on the contrary, it very felt strange to them.