This bug happens in 1.9.04 and cannot recreate in 1.9.07.
Cannot find update log of 1.9.07 so I'm not sure if it's officially fixed or just interfered by other fixed.So I report it here for archive purpose.

Content and readme file are provided in attachment.

====ReadMe content start====
Bug description:
Cannot select or delete exist event in keyframe.

Environment:
Spine Version 1.9.04(Maybe fixed in 1.9.07)

How to recreate bug:
1.Switch to Animation Mode
2.Select animation track "aniAttack"
3.Open dopesheet panel and scroll down to events
4.Try to select event "eventAtkEmit1" or "eventHitPhase1End" and it will be failed.
5.Try to delete these 2 event from Hierarchy panel and the program will crash.

Note:
Images in this project is removed intentionally.It's not relavant to this bug.
====ReadMe content end====

Thanks Nate!
It's great to hear that it's confirmed fixed.
And thanks for the changelog url....I will check it before report other bugs later. =)