Program: 36614
Project: 36614
Buggy source:
@Override public void init(){
  Thumbnail thumb=new Thumbnail();
  thumb.setBorderToImage(true);
  layout=new ImageFlowPane(entireArea,thumb);
  layout.setMinContentWidth(200);
  layout.setMinContentHeight(120);
  layout.setGap(5);
  tiles.widthProperty().addListener((o,ov,nv) -> resize(nv.doubleValue(),tiles.getHeight()));
  tiles.heightProperty().addListener((o,ov,nv) -> resize(tiles.getWidth(),nv.doubleValue()));
  tiles.setAlignment(TOP_LEFT);
  tiles.setTileAlignment(CENTER_LEFT);
  rating.setGraphic(rater);
  rating.setContentDisplay(ContentDisplay.RIGHT);
  labels=Arrays.asList(title,track,disc,gap1,artist,album,album_artist,year,genre,composer,publisher,gap2,rating,playcount,comment,category,gap3,filesize,filename,format,bitrate,encoding,location);
  layout.addChild(tiles);
  Util.setAnchors(tiles,3);
  rater.max.bind(App.maxRating);
  rater.partialRating.bind(App.partialRating);
  rater.updateOnHover.bind(App.hoverRating);
  rater.editable.bind(App.allowRatingChange);
  rater.setOnRatingChanged(r -> MetadataWriter.useToRate(data,r));
  rater.setOnMouseClicked(e -> {
    if (e.getButton() == SECONDARY)     rater.toggleSkin();
  }
);
  rater.visibleProperty().bind(rating.disabledProperty().not());
  thumb.getPane().setOnMouseClicked(e -> {
    if (e.getButton() == PRIMARY) {
      layout.toggleShowContent();
      showFields.setValue(layout.isShowContent());
    }
  }
);
  entireArea.setOnDragOver(DragUtil.audioDragAccepthandler);
  entireArea.setOnDragEntered(e -> {
    if (hasImage(e.getDragboard())) {
      ((Area)getActivityNode().getUserData()).setActivityVisible(true);
      entireArea.getScene().getWindow().requestFocus();
    }
  }
);
  entireArea.setOnDragDropped(e -> {
    if (DragUtil.hasAudio(e.getDragboard())) {
      List<Item> items=DragUtil.getAudioItems(e);
      if (!items.isEmpty())       populateGui(items.get(0).getMetadata());
      e.setDropCompleted(true);
      e.consume();
    }
  }
);
  actPane=new ActionChooser();
  actPane.setOnDragExited(e -> ((Area)actPane.getUserData()).setActivityVisible(false));
  Labeled copyB=actPane.addIcon(PLUS_SQUARE,"String_Node_Str");
  copyB.setOnDragOver(DragUtil.imageFileDragAccepthandler);
  copyB.setOnDragDropped(e -> {
    if (data != null && data.isFileBased()) {
      DragUtil.doWithImages(e,imgs -> {
        int n=imgs.size();
        if (n == 1) {
          copyFileSafe(imgs.get(0),data.getLocation(),"String_Node_Str");
          Platform.runLater(cover_source::applyValue);
        }
 else         if (n > 1) {
        }
      }
);
      ((Area)actPane.getUserData()).setActivityVisible(false);
      e.setDropCompleted(true);
      e.consume();
    }
  }
);
  Labeled coverB=actPane.addIcon(PLUS,"String_Node_Str");
  coverB.setOnDragOver(DragUtil.imageFileDragAccepthandler);
  coverB.setOnDragDropped(e -> {
    if (data != null && data.isFileBased()) {
      DragUtil.doWithImages(e,imgs -> copyFiles(imgs,data.getLocation()));
      ((Area)actPane.getUserData()).setActivityVisible(false);
      e.setDropCompleted(true);
      e.consume();
    }
  }
);
  Labeled lvlB=actPane.addIcon(SQUARE_ALT,"String_Node_Str","String_Node_Str",false);
  lvlB.setContentDisplay(CENTER);
  lvlB.setOnMouseClicked(e -> {
    if (e.getButton() == PRIMARY) {
      lvlB.setText("String_Node_Str");
    }
    if (e.getButton() == SECONDARY) {
      lvlB.setText("String_Node_Str");
    }
    e.consume();
  }
);
}

Fixed version (ground truth):
@Override public void init(){
  Thumbnail thumb=new Thumbnail();
  thumb.setBorderToImage(true);
  layout=new ImageFlowPane(entireArea,thumb);
  layout.setMinContentWidth(200);
  layout.setMinContentHeight(120);
  layout.setGap(5);
  tiles.widthProperty().addListener((o,ov,nv) -> resize(nv.doubleValue(),tiles.getHeight()));
  tiles.heightProperty().addListener((o,ov,nv) -> resize(tiles.getWidth(),nv.doubleValue()));
  tiles.setAlignment(TOP_LEFT);
  tiles.setTileAlignment(CENTER_LEFT);
  rating.setGraphic(rater);
  rating.setContentDisplay(ContentDisplay.RIGHT);
  labels=Arrays.asList(title,track,disc,gap1,artist,album,album_artist,year,genre,composer,publisher,gap2,rating,playcount,comment,category,gap3,filesize,filename,format,bitrate,encoding,location);
  layout.addChild(tiles);
  Util.setAnchors(tiles,3);
  rater.icons.bind(App.maxRating);
  rater.partialRating.bind(App.partialRating);
  rater.updateOnHover.bind(App.hoverRating);
  rater.editable.bind(App.allowRatingChange);
  rater.setOnRatingChanged(r -> MetadataWriter.useToRate(data,r));
  rater.setOnMouseClicked(e -> {
    if (e.getButton() == SECONDARY)     rater.toggleSkin();
  }
);
  rater.visibleProperty().bind(rating.disabledProperty().not());
  thumb.getPane().setOnMouseClicked(e -> {
    if (e.getButton() == PRIMARY) {
      layout.toggleShowContent();
      showFields.setValue(layout.isShowContent());
    }
  }
);
  entireArea.setOnDragOver(DragUtil.audioDragAccepthandler);
  entireArea.setOnDragEntered(e -> {
    if (hasImage(e.getDragboard())) {
      ((Area)getActivityNode().getUserData()).setActivityVisible(true);
      entireArea.getScene().getWindow().requestFocus();
    }
  }
);
  entireArea.setOnDragDropped(e -> {
    if (DragUtil.hasAudio(e.getDragboard())) {
      List<Item> items=DragUtil.getAudioItems(e);
      if (!items.isEmpty())       populateGui(items.get(0).getMetadata());
      e.setDropCompleted(true);
      e.consume();
    }
  }
);
  actPane=new ActionChooser();
  actPane.setOnDragExited(e -> ((Area)actPane.getUserData()).setActivityVisible(false));
  Labeled copyB=actPane.addIcon(PLUS_SQUARE,"String_Node_Str");
  copyB.setOnDragOver(DragUtil.imageFileDragAccepthandler);
  copyB.setOnDragDropped(e -> {
    if (data != null && data.isFileBased()) {
      DragUtil.doWithImages(e,imgs -> {
        int n=imgs.size();
        if (n == 1) {
          copyFileSafe(imgs.get(0),data.getLocation(),"String_Node_Str");
          Platform.runLater(cover_source::applyValue);
        }
 else         if (n > 1) {
        }
      }
);
      ((Area)actPane.getUserData()).setActivityVisible(false);
      e.setDropCompleted(true);
      e.consume();
    }
  }
);
  Labeled coverB=actPane.addIcon(PLUS,"String_Node_Str");
  coverB.setOnDragOver(DragUtil.imageFileDragAccepthandler);
  coverB.setOnDragDropped(e -> {
    if (data != null && data.isFileBased()) {
      DragUtil.doWithImages(e,imgs -> copyFiles(imgs,data.getLocation()));
      ((Area)actPane.getUserData()).setActivityVisible(false);
      e.setDropCompleted(true);
      e.consume();
    }
  }
);
  srcB=actPane.addIcon(SQUARE_ALT,"String_Node_Str");
  srcB.setOnMouseClicked(e -> {
    if (e.getButton() == PRIMARY)     readMode.setNextNapplyValue();
    if (e.getButton() == SECONDARY)     readMode.setPreviousNapplyValue();
    ReadMode r=readMode.getValue();
    GlyphIconName i=r == PLAYING ? PLAY : ANDROID;
    srcB.setText(i.characterToString());
    srcB.setStyle(String.format("String_Node_Str",i.getFontFamily(),15));
    srcB.getStyleClass().add("String_Node_Str");
    actPane.description.setText("String_Node_Str" + readMode.getValue().toString() + "String_Node_Str"+ readMode.next().toString()+ "String_Node_Str"+ "String_Node_Str"+ readMode.getValue().toString()+ "String_Node_Str"+ readMode.previous().toString());
  }
);
  srcB.setOnMouseEntered(e -> {
    actPane.description.setText("String_Node_Str" + readMode.getValue().toString() + "String_Node_Str"+ readMode.next().toString()+ "String_Node_Str"+ "String_Node_Str"+ readMode.getValue().toString()+ "String_Node_Str"+ readMode.previous().toString());
  }
);
  Labeled lvlB=actPane.addIcon(SQUARE_ALT,"String_Node_Str","String_Node_Str",false);
  lvlB.setContentDisplay(CENTER);
  lvlB.setOnMouseClicked(e -> {
    if (e.getButton() == PRIMARY) {
      lvlB.setText("String_Node_Str");
    }
    if (e.getButton() == SECONDARY) {
      lvlB.setText("String_Node_Str");
    }
    e.consume();
  }
);
}