Great Info, THX!
With the new navigation manager in 4.2 still not allowing you to add drop down menu to parent tabs

; would it be best practice on 4.2.1 to add a tab with the default nav. man. and then just update the corresponding tabs code in forumdisplay.php with your code in step 2? If that makes sense
OR forget nav. man. and just insert your step 2 code after {vb:raw navigation} in navbar template; Like this-
https://vborg.vbsupport.ru/showthread.php?t=246687