One thing to remember here is that intellisense is an approximation of what's allowed and legal in the program. It's goal is to be very close to true but often isn't. There are several reasons why a particular type may or may not show up in intellisense but does in C#
- One of the 2 projects may be friends with the target assembly
- Intellisense filters may exist on the documentation files which hide them from intellisense
- Attribute filters on the type
- Certain classes may get hidden due to case only differences in the name
Given that it also doesn't show up in the object browser, my guess is that the class has either intellisense or attribute filters that cause it to be hidden for VB.Net.