private void onOkAction() {
        if (dialogActionHandler != null) {
            dialogActionHandler.onDialogAction(DialogAction.OK);
        }
    }
Notify the dialog when either the Enter or Escape key is pressed.
For dialogs with a close button, the Escape will cause them to close.
The combination Ctrl+Enter key will close the dialog, with a `true` result.
stroom-core-client-widget/src/main/java/stroom/widget/popup/client/view/AbstractPopupPanel.java