Intellisense and context help for sys stored procedures - bugs or by design ?

Answer 1

You are missing a '

sp_cdc_enable_table 'dbo', FactInternetSales' 
                          ^ here

Change it to:

sp_cdc_enable_table 'dbo', 'FactInternetSales' 

And it should fix your problem.

Answer 2

According to the MSDN documentation here, @role_name must be specified.

[ @role_name = ] 'role_name'

Is the name of the database role used to gate access to change data. role_name is sysname and must be specified. If explicitly set to NULL, no gating role is used to limit access to the change data.

If the role currently exists, it is used. If the role does not exist, an attempt is made to create a database role with the specified name. The role name is trimmed of white space at the right of the string before attempting to create the role. If the caller is not authorized to create a role within the database, the stored procedure operation fails.