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That is not possible to do on the server side. However, by making a custom version of the text field it should be possible, see https://vaadin.com/docs/-/part/framework/gwt/gwt-overview.html on how that is done. See this old link for how the event is then disabled on the client-side: https://coderanch.com/t/515153/framework/Disable-Copy-Paste-Textbox.