If you get a message saying that your Java Plugin is not supported when you go to share a screen in “Sametime” you need to adjust your chrome settings as per this note https://www.java.com/en/download/faq/chrome.xml
The change takes a few seconds :

  1. In your URL bar, enter:
  2. Click the Enable link for the Enable NPAPI configuration option.
  3. Click the Relaunch button that now appears at the bottom of the configuration page.