ControlsFX class Dialogs is marked as deprecated.
What to use instead?
This blog post explains it all:
http://fxexperience.com/2014/09/announcing-controlsfx-8-20-7/
This release has been brewing since 8.0.6 was released on May 29th – so basically four months. This is not typical for us (we normally have much quicker releases), but Eugene and I were both distracted on a major undertaking – elevating the ControlsFX dialogs API and implementation into the next release of JavaFX itself (it’ll be appearing in JavaFX 8u40, although the API is vastly different than what you see in ControlsFX 8.0.6). The end result is that we iterated through a bunch of API design work (see RT-12643) and none of that benefited ControlsFX, but it took up all our time.
Once JavaFX 8u40 dialogs were API complete (which was only mid-August), we developed a plan for how to proceed with ControlsFX dialogs. In essence we didn’t feel that it was wise to maintain a dialogs API in ControlsFX that was so divergent than what will ship in JavaFX 8u40. Therefore, the plan that we developed was to deprecate the old ControlsFX API, fork the JavaFX dialogs API into a new project called openjfx-dialogs, and to recreate the additional features that ControlsFX includes (but are lacking in JavaFX itself) using the new API (this includes dialogs like progress, font chooser, command link, login, etc).