Take a DataRow type variable for example called dr. When you just typed dr. the Intellisense autolists all the members for that type or instance. At least the expectation is that it should. There is though a setting to hide “advanced” members ( honestly I don’t know the criteria based on which some members are advanced and some others are not). In the case of the <DataRow dr> variable that we took as an example you will not get listed by default methods like: BeginEdit, CancelEdit, EndEdit … and probably many others. Again this is happening by default in VS 2010 RC. I tried the same thing in VS 2008 and it showed all the members.
You can find the setting in Tools\Options\Text Editor\All languages or individual languages
I believe that the “Hide advanced members” is in an undefined state because it tries to reflect the cumulated state of this flag for all the languages and some don’t even have this option (it’s greyed out) like VB for example.
To be sure that for example in C# you get all the members go to C#’s page and uncheck the setting there.
Take a look at the Parameter Information checkbox setting and make a note of it. You should check this if you find at one point that you don’t get method parameter information anymore.