Top-level space "hijacking"

If I create a new public space _Fruit_ that I am an admin of then it will show up as a top-level space in the spaces sidebar. However at some point in the future some other person with no connection for the original _Fruit_ space might create a public _Food_ space and decide to add _Fruit_ as a subspace. If I (or another user who is already a member of the _Fruit_ space) decides to join the _Food_ space then suddenly I no longer have the _Fruit_ space show up as a top-level space in the sidebar.

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As a user if you aren't paying attention you might not even notice that _Fruit_ is now a sub-space and just notice that it is missing from the top-level spaces. Assuming you even know what has happened you need to click through all the spaces/sub-spaces to find which one it is in.

As an admin of the _Fruit_ space but not the _Food_ space it also seems rather counter-intuitive that I need to click through other spaces to get to the space I'm an admin of to manage it.

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At a minimum for the user there should be a way to pin a sub-space (ie. _Fruit_) as a top-level space. When you first join a space that is not already a sub-space of another space you are in when you first join it, it should be pinned by default. If at a later point the you find yourself as a member of a top-level space (ie. _Food_) and a pinned sub-space (ie. _Fruit_) you can then unpin the sub-space.

For admins it might be desirable to somehow mark a space as not being able to be added as a sub-space to a non-private space.