When a Button is placed in a ListCell (or probably any other Cell) its onAction event is never fired and onMouseClicked very rarely and seemingly randomly. Found on JDK8 RC. Here is some example code:

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ListCell;
import javafx.scene.control.ListView;
import javafx.stage.Stage;

public class Testing extends Application {

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        ObservableList<String> strings = FXCollections.observableArrayList();
        strings.addAll("text", "another");
        ListView<String> list = new ListView<>(strings);
        list.setCellFactory(cell -> new ButtonCell());
        Scene s = new Scene(list, 300, 400);
        primaryStage.setScene(s);
        primaryStage.show();
    }

    private class ButtonCell extends ListCell<String> {

        @Override
        protected void updateItem(String item, boolean empty) {
            super.updateItem(item, empty);
            if (empty) {
                setText(null);
                setGraphic(null);
            } else {
                setText(item);
                Button b = new Button("button");
                b.setOnAction(action -> System.out.println("zam"));
                b.setOnMouseClicked(action -> System.out.println("bam"));
                setGraphic(b);
            }
        }
    }
}

WORKAROUND... return from updateItem if the cell's index has not changed.

    private class ButtonCell extends ListCell<String> {

        int currentIndex = -1;
        @Override
        protected void updateItem(String item, boolean empty) {
            super.updateItem(item, empty);
            if (empty) {
                setText(null);
                setGraphic(null);
            } else {
                int index = getIndex();
                if (currentIndex == index) return;
                currentIndex = index;
                setText(item);
                Button b = new Button("button");
                b.setOnAction(action -> System.out.println("zam"));
                b.setOnMouseClicked(action -> System.out.println("bam"));
                setGraphic(b);
            }
        }

    }