Hi Tom,
I am afraid that made it worse. The menu now behaves as such:
1. Main Navigation (page scrolled up to the top): When I click on a main navigation item, I am guided to the location and the menu closes (this works well as previously)
1.1. Main Navigation (page scrolled mid-way): When I click on a main navigation item, I am guided to the location but the menu does not close
2. Subnavigation (both cases, scrolled up and midway): When I open the subnavigation menu, the entire menu closes, before I get the chance to click on a link
Cheers,
Calvin