The way that copying from the preview pane works now is incredibly annoying. It tries to copy the entire thing, even if you’ve only selected one portion. Additionally, it copies all the HTML formatting. More often than not, my instance also crashes whenever I do a copy.
I propose that copy in the preview pane works as you would expect, i.e., only the selected part is copied and the formatting is maintained in much the same way as it would be if you were copying text from a web page. In this way, you usually have the option to paste just the text or retain formatting such as bold, etc.