You can update, rename, share, hide (only hidden on your Shortcut, not globally), delete or re-save a Space by hovering over the name and selecting your action (press the ellipsis for more actions).
You can also press the ellipsis icon to view the name of a Space if it has been cut-off in the regular display.
To update a Space's filters, choose the Space you'd like to modify, and make any changes to the filtering that you want.
You'll see that it'll deselect the Space and highlight 'Unsaved Space' -- don't worry about that.
Instead, hover over the Space you're making the change to, and then click on the 'Save' button in the pop up menu. You should see an alert confirming that the Space was updated in the lower right corner of your browser:
If you make edits to or save a Space you did not mean to alter or create, you can undo your actions by clicking "Undo" on the success message that briefly appears in the bottom right-hand corner when changes to the Space are saved.