Cannot edit an element's existing content unless tags: null

[nrkn]

If the element starts out empty, you can type some text in and format it with for example CTRL+B (see element 1 in the fiddle below)

If the element has existing content, when you select it and attempt to format it with CTRL+B, the formatting immediately reverts (see element 2 in fiddle)

If tags: null is passed in the options, you can edit the existing content without it reverting (see element 3 in fiddle)

http://jsfiddle.net/nrkn/2kbr11cg/1/