This image shows the OnEvent dialog. At the top are the Message Exchange, Documentation, Properties, General, and Correlations tabs. Below this is the Partner Link field (with a Search icon to the right), Port Type list, and Operation list. Below this are the Variable radio button (selected) and From Parts radio button. Below this is the Variable field. Below this is the Data Types section, with the Message Type and Elements radio buttons. Both buttons have a Search icon to the right.