Postorius gets confused in showing views for members with multiple roles

To reproduce The Bug:
If any member (other than superuser) is granted multiple roles : owner and moderator at once, Postorius doesn't give the correct view for the nav bar and doesn't show all the actions which can be performed by the user.

Clicking on Held Messages from while on the summary page only shows the tabs to be shown for moderator roles and not all since the user is also privileged with owner access.
Similarly, accessing Delete a List from summary page only shows that for owner roles and not for that of moderators...

Thus, The Bug needs to be fixed since the user should be given a complete control based on his access level in the lists.