I have inadvertently deleted a data, but clicking “undo” does not restore me the missing data.
Many thanks.
Welcome!
Contact the chat support. They can help you.
Hi @UnicaMente Welcome to the community, happy to see you around 
When it comes to the deletion of your data (folders, items or attributes) you will be able to restore your data by going into the board manager -> trash -> and then restoring exactly what you have deleted or basically permanently deleting it from the board.
Let me show you where you can find those options:
Once you click restore, the item will go back to its original place and you will be able to use it, edit it, change it or do anything else you want with it.
So, if you miss the “undo” button in the bottom right corner, you can always go to the board manager and get your data back through it. 