Program: 49859
Project: 49859
Buggy source:
private void initComponents(){
  setLayout(new GridBagLayout());
  GridBagConstraints constraints=new GridBagConstraints();
  Board[] boards=mGame.getBoards();
  IntStream.range(0,boards.length).forEach(boardIndex -> {
    mGameBoards[boardIndex]=new BoardPanel(boards[boardIndex].getBoardSize(),mSquareConfig,coordinate -> {
      Piece piece=mGame.getPiece(boardIndex,coordinate);
      if (piece != null && piece.getTeamId() == mGame.getTurnKeeper().getActiveTeamId()) {
        return mGame.getMovesFrom(boardIndex,coordinate);
      }
 else {
        return Collections.emptySet();
      }
    }
);
    constraints.gridx=boardIndex;
    constraints.weightx=1.0;
    constraints.weighty=1.0;
    constraints.gridheight=2;
    constraints.fill=GridBagConstraints.BOTH;
    constraints.insets=new Insets(10,0,0,0);
    add(mGameBoards[boardIndex],constraints);
  }
);
  Stream.of(mGame.getTeams()).forEach(team -> mTeamStatusPanels.add(new TeamStatusPanel(team)));
  mTeamStatusPanels.forEach(panel -> mTabbedPane.addTab(panel.getName(),panel));
  constraints.gridx=boards.length * 2;
  constraints.weightx=0.3;
  constraints.gridheight=1;
  constraints.weighty=1.0;
  constraints.insets=new Insets(0,25,0,10);
  add(mTabbedPane,constraints);
  mUndoButton.addActionListener(event -> {
    mGame.undoMove();
    refresh();
  }
);
  mForwardButton.addActionListener(event -> {
    mGame.nextMove();
    refresh();
  }
);
  mBackButton.addActionListener(event -> {
    mGame.previousMove();
    refresh();
  }
);
  GridBagConstraints gbc=new GridBagConstraints();
  JPanel buttonPanel=new JPanel();
  buttonPanel.setLayout(new GridBagLayout());
  buttonPanel.setOpaque(false);
  gbc.gridy=0;
  gbc.gridx=0;
  gbc.gridwidth=2;
  gbc.weightx=1.0;
  gbc.fill=GridBagConstraints.BOTH;
  buttonPanel.add(mUndoButton,gbc);
  gbc.gridy=1;
  gbc.gridx=0;
  gbc.gridwidth=1;
  buttonPanel.add(mBackButton,gbc);
  gbc.gridx=1;
  buttonPanel.add(mForwardButton,gbc);
  constraints.gridy=1;
  constraints.gridx=boards.length * 2;
  constraints.weighty=0.2;
  add(buttonPanel,constraints);
  refresh();
}

Fixed version (ground truth):
private void initComponents(){
  setLayout(new GridBagLayout());
  JPanel boardPanels=new JPanel();
  boardPanels.setOpaque(false);
  boardPanels.setLayout(new GridBagLayout());
  Board[] boards=mGame.getBoards();
  IntStream.range(0,boards.length).forEach(boardIndex -> {
    mGameBoards[boardIndex]=new BoardPanel(boards[boardIndex].getBoardSize(),mSquareConfig,coordinate -> {
      Piece piece=mGame.getPiece(boardIndex,coordinate);
      if (piece != null && piece.getTeamId() == mGame.getTurnKeeper().getActiveTeamId()) {
        return mGame.getMovesFrom(boardIndex,coordinate);
      }
 else {
        return Collections.emptySet();
      }
    }
);
    GridBagConstraints gridBagConstraints=new GridBagConstraints();
    gridBagConstraints.gridx=boardIndex;
    gridBagConstraints.fill=GridBagConstraints.BOTH;
    gridBagConstraints.weightx=1.0;
    gridBagConstraints.weighty=1.0;
    boardPanels.add(mGameBoards[boardIndex],gridBagConstraints);
  }
);
  Stream.of(mGame.getTeams()).forEach(team -> mTeamStatusPanels.add(new TeamStatusPanel(team)));
  mTeamStatusPanels.forEach(panel -> mTabbedPane.addTab(panel.getName(),panel));
  mUndoButton.addActionListener(event -> {
    mGame.undoMove();
    refresh();
  }
);
  mForwardButton.addActionListener(event -> {
    mGame.nextMove();
    refresh();
  }
);
  mBackButton.addActionListener(event -> {
    mGame.previousMove();
    refresh();
  }
);
  GridBagConstraints gbc=new GridBagConstraints();
  JPanel detailsPanel=new JPanel();
  detailsPanel.setLayout(new GridBagLayout());
  detailsPanel.setOpaque(false);
  gbc.gridwidth=2;
  gbc.weightx=1.0;
  gbc.fill=GridBagConstraints.BOTH;
  gbc.weighty=1.0;
  gbc.insets=new Insets(0,10,10,10);
  detailsPanel.add(mTabbedPane,gbc);
  gbc.gridy=1;
  gbc.gridx=0;
  gbc.gridwidth=2;
  gbc.weighty=0.0;
  detailsPanel.add(mUndoButton,gbc);
  gbc.gridy=2;
  gbc.gridx=0;
  gbc.gridwidth=1;
  detailsPanel.add(mBackButton,gbc);
  gbc.gridx=1;
  detailsPanel.add(mForwardButton,gbc);
  GridBagConstraints constraints=new GridBagConstraints();
  JSplitPane splitPane=new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,boardPanels,detailsPanel);
  splitPane.setPreferredSize(new Dimension(755,475));
  splitPane.setDividerLocation(450);
  splitPane.setOpaque(false);
  splitPane.setDividerSize(1);
  splitPane.setResizeWeight(0.7);
  splitPane.setEnabled(false);
  constraints.weightx=1.0;
  constraints.weighty=1.0;
  constraints.gridheight=1;
  constraints.fill=GridBagConstraints.BOTH;
  add(splitPane,constraints);
  refresh();
}