Ctrl, shift and right clicks with DomEvent and GridContextMenuClickEvent

ClickEvent has getButton and isCtrlKey etc.

In LitRenderer I can do a @click="${ (e) => click(e.shiftKey, e.ctrlKey) } and add .withFunction("click", ...)

But what can I do with DomEvent and GridContextMenuClickEvent to find out if a click was with shift or ctrl?

With GridContextMenuClickEvent, you’d need to make a change in the component’s implementation to pass the information to the event object. I’d recommend starting by creating an issue in GitHub - vaadin/flow-components: Java counterpart of Vaadin Web Components

For DomEvent, take a look at Using Events | Creating Components | Creating UI | Vaadin Docs (which is also the way you’d need to change the grid context menu click event).