code: private void checkForPrompt() {
          //  Text has been entered, remove the prompt
  
          if (document.getLength() > 0) {
              setVisible(false);
              return;
          }
  
          //  Prompt has already been shown once, remove it
  
          if (showPromptOnce && focusLost > 0) {
              setVisible(false);
              return;
          }
  
          //  Check the Show property and component focus to determine if the
          //  prompt should be displayed.
  
          if (component.hasFocus()) {
              if (show == Show.ALWAYS
                      || show == Show.FOCUS_GAINED)
                  setVisible(true);
              else
                  setVisible(false);
          } else {
              if (show == Show.ALWAYS
                      || show == Show.FOCUS_LOST)
                  setVisible(true);
              else
                  setVisible(false);
          }
      }
docs: Check whether the prompt should be visible or not. The visibility
  will applyChanges on updates to the Document and on focus changes.