Controller auto-suggest does not work just after FXML is saved inside project

(Following the tutorial step by step…)

Create IssueTrackingLite FXML (or subset thereof), and save the file inside the Sample folder, where the Java files are already present.
Open the Controller section.
Bug: The Controller class editor does not make any suggestion.

Close and re-open the file.
The Controller class editor finds and suggests the controller class.