In version 1.0.216, running n Windows 10, the new toolbar has an expected effect that might catch you out. It caught me out 
I have borrowed this screen shot to make clear what I am talking about. (The red circle is not relevant here.)
I have the Layout button set to show Viewer / Split View. I edited a note in split view and then switched to the viewer. The formatting buttons remained visible, even though formatting was not possible.
I accidentally pressed the H button on the formatting bar and, to my surprise, a chunk of text suddenly became formatted as a header. I went back into the editor and looked and I had left my cursor just before a word in the middle of the sentence. The H button had formatted the rest of the sentence as a heading even though I was supposed to be in the viewer.
Is this by design or a bug? IMO the format bar should disappear when formatting is not supposed to be active.
Cheers
Owen