Thanks, this was a genuine bug.
Event descriptions belong on event definitions, not event handlers. Studio was incorrectly applying the missing-description warning to generated handler methods like Button1_Pressed, then displaying that as Button1.Pressed. Since event handlers intentionally do not expose a Description field, there was no way to resolve the warning from the UI.
Fixed for the next release (https://feedback.objo.dev/bug/440). Missing-description warnings will still apply to actual event definitions, methods, constructors, properties, and constants, but recognised event handlers will no longer produce this warning.