Here are some suggestions to improve editing events:
1.) I can't copy&paste an action to an event if that event has no any action defined in it, but this is possible if that event has at least one action already defined. So in that case, instead of copy&paste an existing action I must again create a new (but the same) action using "Add Action" button.
2) Why I can't add a new global variable at the top of the event sheet during its creation? Now it is always created at the bottom and I must move it up if I want to have all global variables listed on the top of the sheet. Maybe, this could be fixed by adding "Insert Global Variable Above/Below" option in the popup menu when right mouse button is clicked on already defined Global Variable or Event?