Details for the issue

What did you do?

Open sqlitebrowser. Create a new In Memory Database (getting the 'main' database in the connection). The "Attach Database" button and File-Menu Action keeps to be disabled.

You are able to attach databases (:memory: or files) manually with sql statements but they don't show up on the Database Structure. What they do proper if you're attached to an proper database file.

Funny thing is, this changes when You add an temporary database object. Then all attached databases show up in both of the Database Structure widgets.

I don't see any use in disabling database attachment on InMemory databases.

Tested on #2241