To remove the current node one should click the "Remove" button on the toolbar to the left of the Inspector and to confirm its intention. This node actually is moved in the position of last child of the "Recycle bin" node of the current subdomain or domain. If such a "Recycle bin" in the domain does not exists, the node is moved to the global Smereka "Recycle bin".
So, if the removal was incorrect, one should go to the corresponding "Recycle bin", find the desired node and click "Restore" button. Then Smereka try to move the node back to the previous hierarchical position (although this is not always possible).
Another "Recycle bin" feature is complete and irrevocable node deletion. While node deleted, all its attributes are deleted too and the size of the database is reduced. After that data recovery is impossible (unless the entire database is restored from a backup).
Please be aware that the removal operation is hierarchical, ie node crown always removed along with master node. This applies to both types of removal – moving in a "Recycle bin" and final deletion from the "Recycle bin". While node deletion all its child nodes also deleted forever.