Draco555 Please log an issue on the feedback site (SQL · Community (azure.com)) with detailed steps to recreate the issue. I'm not clear what "test it with security policy that has more than one session context" means, and having a list of steps would extremely helpful.
gotqn The changes I've described in this post are the scope for SSMS 20. For the requests you've listed above, I highly recommend going to the feedback site (SQL · Community (azure.com)), searching for similar requests (I know at least two of the three already exist) and then upvoting those and adding comments. If there is no existing request, feel free to add it. We use the feedback site to understand customer interest and make changes accordingly.
sqlmonk We will not have changes related to dark mode in SSMS 20.