Deleting an app from the "My Shared Apps" page (via the profile icon in the top blue bar) only deletes the share. It doesn't affect any installations of that app in your workspace.
If you delete the original app that was shared, then this also deletes the share. Note that this is only for the original - if you delete any of the additional installations of the app, this does not affect the share.
Hope that makes sense?
/Jacquelyn - Podio