1) In Options > Controls > Common, delete all the default keybindings for "Use default action" as well as "Use selected action" and assign them to two different keys: for example E for "Use default action" and Q for "Use selected action"
2) In the editor, place a player Explosive Specialist in an empty field of Stratis
3) In game, press E and notice the Action menu showing up even if you are in the middle of nowhere and there are no interactive objects available around you.
4) With the Action menu open, press E and see how you can place mines the same as you do with Q