Contextual Filters and Menu

Hello,

since a long time I'm trying to include the links to my views in the menu. But there are several problems I can't solve.

My view has a path f.e. downloads. With contextual filters (taxonomy id), that I'm using in the URL the view shows different nodes. I'm using the urls in a hierarchical menu:

f.e.
downloads/1
-dowloads/1a
-downloads/1b
downloads/2

One of the problems is, that the menu does not expand when above link is activated.
f.e. When clicking on downloads/1, the menu still looks like

downloads/1
downloads/2

the only solution is, to set downloads/1 to expanded by default.

Why is the menu item not expanding when activated?
I have this problem only with views where I'm using these contextual filters for the url

Thanks and regards

Adriana