I want to use SHIFT + ENTER shortcut to insert a line break and continue inside the same parahraph. However RTC is creating a new paragraph which looks very bad.
Unfortunately, there’s no built-in way in Vaadin’s RichTextEditor to make Shift + Enter produce a soft break (i.e., a <br>instead of a new <p>), AFAIK. The component’s HTML support does allow <br>, but when editing, it re-parses and forces <p> tags.
There is an open GitHub issue for this missing behavior. One possible workaround is to work with the editor’s HTML or Delta value programmatically: after the user inputs text, intercept the value, replace <p></p> pairs (or </p><p>) with <br>, then set it back. It’s a bit hacky, but that’s what’s feasible for now.
Also worth noting: newer versions of Vaadin (or alpha/preview builds) may include updates — for example, Vaadin 25’s upcoming Quill integration might behave differently, so it’s worth testing if you can.