Database Tree Displaying Unwanted Databases

My database tree currently displays, along with my created databases, 'information_schema', 'mysql', 'performance_schema', & 'sys' databases.

These are just cluttering up the tree so:

a) are these databases necessary or can they be deleted? b) if they cannot be deleted, is there any way to hide them in the tree without using the filter?

Thanks

a) no, definitely do not delete them. All of them are known system databases. If you delete them, you will break the servers integrity and you will probably lose access to your "normal" databases

b) you can limit the displayed databases in the session manager:

Hi Ansgar

That's great, thank you.

Couldn't find anything about that in the help section so perhaps it could be added?

Thanks again

Yes, the help page... it's mostly outdated, so thanks for the hint. I just added descriptions for some terms used on the session manager, including the databases thing.