In one of my note, I can't paste things anymore and the controls are getting weird

In one of my note, I can't paste things anymore and the controls are getting weird

One of my note is getting very weird.

I can't paste anything anymore, there's a problem when I try to edit the text etc.

It's difficult to explain, so here's a short screencast: http://somup.com/c3VFD5Z07g