When you open Window->Class Viewer, not all classes have the Button (which simulating RMB) on their right side, but when you press RMB on some class without that button, then this button appears, and even more, some of the buttons may dissappear also and appear in another class, also when you press RMB on class without visible button.
PS: RMB - right mouse button.
Hello,
Thank you for your report. We were not able to investigate this on the engine version you reported, but there have been many version changes to UE4 since this question was first posted. With a new version of the Engine comes new fixes and it is possible that this issue has changed or may no longer occur. Due to timetable of when this issue was first posted, we are marking this post as resolved for tracking purposes.
If you are still experiencing the issue you reported in the current engine version, then please respond to this message with additional information and we will investigate as soon as possible. If you are experiencing a similar, but different issue at this time, please submit a new report for it.
Thank you.