VS2008 Setup Project Dependencies bug ?

My solution contains an app project, dll project and 2 setup projects. The app is dependent on the dll and both come in 2 build configurations, let's say Config1 and Config2. When I switch between these configurations, the app project references the appropriate dll build ... so far so good ! However, switching between configurations messes up the setup project dependencies ! Switching to e.g. Config2 causes the Config1 setup project to show the Config2 dll as a dependency ... and vice versa. In order to build my setups correctly I need to select the configuration of the setup project I want to build , update depencies and then it's ok. Is this how it's supposed to be or rather an IDE bug ?