How do I force ONLY those entries with a certain tag to appear by default?

Hi there @HippopotamusMan

In this particular situation, I'd suggest the following:

1. Create a new vault called something meaningful like Startup or whatever you like.
2. Move the items with the appropriate tag into that new vault.
3. Create a collection containing that vault.

Then, when you choose that collection at the top of the sidebar, 1Password will remember which one is active.

If you want, you can include multiple vaults (even from multiple accounts if you have them) in the same collection. For example, I have an "Everyday" collection which has some of my work vaults and my personal vaults, but none of my testing stuff to keep it streamlined.

It might be worth having a play about with vaults and collections to get things set up the way you want. Let me know how you get on or if I can be of any help. :)

— Grey