There is few ways to access to the protein group detail page :
Compare context with each other
result table : click in one of the Protein(ref) or Protein(comp) cells to update the protein group view. A Protein Group window should be opened. If it is not the case, first open one by selecting menu Window > Protein Group
Compare context with Child
result full table : click on one row to update the protein group view with the parent context protein group information. If there is no protein group window opened, right-click on a row in the result table and select View Protein
In all case it is possible to stop updating the protein group window using the right-upper corner pin icon. In this case, for any other protein group detail view, a new protein group window should be opened.