Note that this isn’t a benign bug.
Because it selects the title across a frame boundary, Cmd-A+Cmd-C still doesn’t work on the Preview pane to copy the previewed note. The extra selection may have been tweaked but the actual effect of the bug (no ability to copy) is still untouched.
Copy/pasting preview-rendered HTML into Google Docs with a subsequent “Clear Format” is by far the easiest way to convert a markdown document to Google Apps without third-party tooling (most of which has corporate security implications). This is pretty important for interchange with people who don’t use Markdown.
This is screwing me up more than a little in that I’m currently having to micromanage the selection with a cursor swipe to give my notes to colleagues.
It’d be really nice if this were fixed. It’s essentially breaking your export function, whether that’s what preview was intended to be or not.