My settings as below:

1. 2 companies  defined, C1 and C2.

2.  2 websites defined,  W1 and W2, W1 for C1 as default website,  W2 for C2.

3.  "Common product catelog" checked.

4.  products of C2  can be listed for portal user on W1 if the   "website " field was set to "W1" , and these products listed  on W2 too, even none of them has "website" field value "W2".

 if i set these products' "website" field to W2 , portal user can not see them on both sites W1 and W2.

Please help, seems that "website" filed don't work properly with Multi website.

Another problem is W2 is showing the same favicon and website tittle with W1, and company logo of C1.