Sounds like it should be there.
Does your synonym show when logged in as UserA in 'select * from user_synonyms' ?
If not, make sure you don't have a filter applied to the syn tree node.
I'm able to see private synonyms on versions 18.104.22.168 and 3.2.20.09
Figured out -- becausethe user is a dba role, when I connect to oracle sql developer I use as sysdba. So then I guess when login it actually is user sys, so sys doesnt have that private synonyms. that is why it is not shown there.
Also I tried to test this theroy in sqlplus, it is easy to connect this DBA role user for example it is called UserMyDBA,
I use sqlplus userMyDBA@DBname, but how can I connect it as a sysdba,
I tried SQLPlus userMyDBA as sysdba;