When trying to adjust line spacing in an HTML form, tables often get deleted when trying to just delete a line space. There is currently no "undo" button. The only way of restoring the deletion is to view the history and copy/paste it back in.
Thank you for your idea. It is currently possible to undo changes while making changes in the text editor using the CTRL+Z keyboard control. This will also include changes to tables, such as accidentally deleting rows or an entire table.