Can't copy and paste keyframes from another action I'm trying to copy some range of keyframes to another action.

In same action, copy and paste works fine, but paste to another action doesn't work.

I mean I have plenty bones but only single bone was pasted, even I selected all bones before copy and paste.




It happens often to me and it's really quite annoying. Why this is happening?
I'm not 100% sure, but mostly it works if I select all bones that have keyframes to copy, both dopesheet and 3d view.

However sometimes it's not working even do that, so that's why I said 100% sure.

I still facing this issue sometimes, but mostly works fine and some how it works after do something try to fix, but don't know what exactly fix this.