use placeholder attribute/prop, which gives us html5-placeholder if supported
Use a textarea for the notes
submit on enter, newline on shift-enter
Fix formatting in firefox

Firefox shows two lines, even if the field is empty. I assume it is
a placeholder for scroll bars that are never shown (Firefox wraps lines, even
without word separators) and setting overflow: none; fixes it.

It has to be !important because otherwise dojo overwrites it with
overflow-x: auto; in the element-style.