More Feature requests: Undo button, split and join lines, configuring what users see who open my map

Undo button:

Having different versions of the map that you can go back to is great, but that does not really work for me.
A simple undo button (and a redo button) would be much more helpful to me! If you make a mistake or change you mind about something, just pressing this button is much simpler. Having lets say 10 of your last actions (for example the removal of a line) stored would be good.

Split and join lines:
Others have already requested this, I would also find this very useful

Configuring what users see who open my map:
Example 1: When opening my map I want the map legend to be expanded by default (exactly in the way it is expanded when i save the map). Otherwise people with not so much computer experience may never find out that they have to press the little triangle to expand the map legend.
Example 2: It would be useful if you could choose the sector of the map that is visible when you open the map. Maybe you have a lot going on, but want to set the focus on a specific area.

Thank you for your amazing work!