now when I drag a keyframe onto another one it just disappears.
do you mean both keyframes disappear? if so, this is weird - only one is supposed to disappear (the previous). please show this step by step with video capture (or even with your phone) or screenshots so we can see what exactly you are doing and what are the results.
Sorry, I should have specified! The ones I'm dragging are the ones that disappear. Also, I did further testing and it's only keyframes that have an expression attached to them that have this issue.
expressions are added to properties so I am not sure what you mean by attached to keyframes. please demonstrate.
I don't have any capture software, but after more testing, the keyframe I'm dragging is actually hiding BEHIND the previous one. If I modify it, to an easyease keyframe, then I can see it behind the previous keyframe(which is set to linear). This is only to explain that because of the different icons for the keyframes I can see the easy eased one behind the linear one. It's not overwriting it for some reason. I just tried opening an older file where this didn't occur and it's still OK, so there's definitely a toggle somewhere or a shortcut or something.
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