Active menu dissapears active

[remco]

Hi,  i have a question

i have a horizontal menu  whit a button called  shop  (joomla 1.7)
now i have virtuemart setup:  (vm2)

• Category1
• Category2
• Category3

now when i press the menu button called shop, the menu item shop gets active and i get to see the categories.
but when i go into a category   the active menu dissapears.
is there a way to get that stay active everywhere in VM?