The problem of saying vietnam conquered Cambodia is the same thing as Vietman is still mad at China...

Lets put the past aside.
However...the latey politics that is going on in Vietnam and SouthEast asia is that Vietnam and Laos and Cambodia have shared the same recent history. The three were toghether in fighting the French.
lately alot of vietnamese investments in Laos. Cooperation has been great than ever. Not only economic cooperation..culture and military aspects also developed.
It is easy to understand. The Three countries geographically closed. The cooperation is always work for the better of all. I mean of course if you put more you get out more. So if Vietman got a big share, then Laos and Cambodia also get their cake. I mean its the same thing as VN does business with her northern neigbor china. China got a bigger share but if the cooperation is beneficial for all of the people, why not do it.
NOt to mentioned, Laos and Vietnam have good tradition relationship. Eventhough Cambodians dont like vietnamese such as Viets dont like chinese, but in the age of global economy...everyone has to eat.
Speically vn will be part of WTO in Nove 7, Laos and Camboida will indirectly select to be affected in term of they will exposed to the kind of things they think good for them.
Its just the way how people these business these days. Not only that, cutural tie also means alot to peace and prosperity of the region.