There is a mode to launch an application/applet in webstart mode via plugin. This mode is used by Deployment Toolkit to launch an FX application in web start mode.

There is a bug in the implementation that such mode should be per-plugin, not a global state. As a result, this can cause crash of browser if both mode are in use. A bug report can be found at http://javafx-jira.kenai.com/browse/RT-13160.