[Bug]: Editing things from a closed library

[SkeleyM]

Checklist

• I have read the documentation.
• I am using an up-to-date version.
• I have searched existing issues.

TagStudio Version

Alpha 9.5.0 (Pre-Release 1)

Operating System & Version

Windows 10 22H2

Description

Closing a library doesn't 'fully' close it
you can still edit tags, create new ones, etc from the previously opened library

Expected Behavior

You shouldnt be able to modify the previous library if you close a library

Steps to Reproduce

1. Open a library
2. close it: file -> close library
3. open manage tags

Logs

No response

[SkeleyM]

the issue seems to be that the engine is not properly cleaned up on closing a library
theres two approaches that I can see and one is
setting engine to None, which causes a whole bunch of errors (all recoverable)
or
explicitly deleting the engine which causes it to be in the same state as when the program starts.
I think the latter is preferable since then there is consistency.
I can submit a pull request for either. I already have tried both so it would be quick for me to do (both one line changes) I'd just like some input on which would be preferable or if theres any other solutions to this that I cant see

[CyanVoxel]

While I'm not able to foresee any potential issues off the top of my head, it seems like your second proposed solution is the better choice 👍

[CyanVoxel]

Lowering the priority of this and #769 now that #787 has been merged