I’m using event handlers extensively.
Now I have the situation where I can’t add an event handler.
After selecting ANY event, hitting the OK button, the Add Event handle window closes and that’s it !!! nothing else displayed.
Save you project, close Xojo, reopen it and see if it was some kind of transient bug.
If it gets bugged constantly, move the class to a sample project and try to replicate the problem there. If you get it, open an Issue report and add the sample.