Multivendor: Cart belongs to the first product vendor

[nordmograph]

Hi

In multivendor mode , (and cart belongs to the fisrst product vendor) when customer tries to add another product from a 2nd vendor, he can't which is fine.
The cart modal window shows up and instead of an explicit warning, only the product name shows.
It should warn something like 'You allready have a product from a different vendor in your cart. You can't add products from various vendors'


Off topic:
What'd be great : a multivendor cart where, if cart has products from various vendors,  shipping costs are added and displayed for each vendors.
(Vendors can set their own shipping rates using the standard shipment method, but these costs can't be added to a cart if more than one vendor in the cart)

Best wishes for the end of the year !