Feedback if we have duplicate topic names in the mind map
Duplicates could be given a special color or symbol, which could be made recognizable by the show/hide feature. Or, even if it's not that straightforward, a filter would somehow automatically capture them all.
In some situations it would be helpful to be able to recognize live if you typed in an identical topic name. A setting in the preferences could do this. E.g. the name would turn red as we type, if it already existed and it would turn black again as soon as we changed a single letter.
Feedback around duplicates could also be interesting when pasting or importing external elements.