Paragraphs on CB

Why do I have to hit enter twice to actually get the CB to switch to a new paragraph.

For instance if I hit "enter" now... even though I go to a new line in the post editor it still reads in the actual post as a single line.

If i hit "enter enter" now...

It shows up as a new paragraph.

Why was this decision made? I'm curious as it seems to be different from every other forum and text editor I've ever used.