Program: 45126
Project: 45126
Buggy source:
private void setupNavigationLinks(){
  add(new AjaxFallbackLink<String>("String_Node_Str"){
    private static final long serialVersionUID=2323006706369304418L;
    @Override public void onClick(    AjaxRequestTarget target){
      if (startY == 1 || startY < 0) {
        startY=1;
        endY=mapDim;
      }
 else {
        startY--;
        endY--;
      }
      target.addComponent(gameMapContainer);
    }
  }
);
  add(new AjaxFallbackLink<String>("String_Node_Str"){
    private static final long serialVersionUID=2323006706369304418L;
    @Override public void onClick(    AjaxRequestTarget target){
      if (endY == gameMapProvider.getMapYSize() || endY < gameMapProvider.getMapYSize()) {
        startY=gameMapProvider.getMapYSize() - mapDim;
        endY=gameMapProvider.getMapYSize();
      }
 else {
        startY++;
        endY++;
      }
      target.addComponent(gameMapContainer);
    }
  }
);
  add(new AjaxFallbackLink<String>("String_Node_Str"){
    private static final long serialVersionUID=2323006706369304418L;
    @Override public void onClick(    AjaxRequestTarget target){
      if (endX == gameMapProvider.getMapXSize() || endX > gameMapProvider.getMapXSize()) {
        startX=gameMapProvider.getMapXSize() - mapDim;
        endX=gameMapProvider.getMapXSize();
      }
 else {
        startX++;
        endX++;
      }
      target.addComponent(gameMapContainer);
    }
  }
);
  add(new AjaxFallbackLink<String>("String_Node_Str"){
    private static final long serialVersionUID=2323006706369304418L;
    @Override public void onClick(    AjaxRequestTarget target){
      if (startX == 1 || startX < 0) {
        startX=1;
        endX=mapDim;
      }
 else {
        startX--;
        endX--;
      }
      target.addComponent(gameMapContainer);
    }
  }
);
}

Fixed version (ground truth):
private void setupNavigationLinks(){
  add(new AjaxFallbackLink<String>("String_Node_Str"){
    private static final long serialVersionUID=2323006706369304418L;
    @Override public void onClick(    AjaxRequestTarget target){
      if (startY == 1 || startY < 0) {
        startY=1;
        endY=mapDim;
      }
 else {
        startY--;
        endY--;
      }
      target.addComponent(gameMapContainer);
    }
  }
);
  add(new AjaxFallbackLink<String>("String_Node_Str"){
    private static final long serialVersionUID=2323006706369304418L;
    @Override public void onClick(    AjaxRequestTarget target){
      if (endY == gameMapProvider.getMapYSize() || endY > gameMapProvider.getMapYSize()) {
        startY=gameMapProvider.getMapYSize() - (mapDim - 1);
        endY=gameMapProvider.getMapYSize();
      }
 else {
        startY++;
        endY++;
      }
      target.addComponent(gameMapContainer);
    }
  }
);
  add(new AjaxFallbackLink<String>("String_Node_Str"){
    private static final long serialVersionUID=2323006706369304418L;
    @Override public void onClick(    AjaxRequestTarget target){
      if (endX == gameMapProvider.getMapXSize() || endX > gameMapProvider.getMapXSize()) {
        startX=gameMapProvider.getMapXSize() - (mapDim - 1);
        endX=gameMapProvider.getMapXSize();
      }
 else {
        startX++;
        endX++;
      }
      target.addComponent(gameMapContainer);
    }
  }
);
  add(new AjaxFallbackLink<String>("String_Node_Str"){
    private static final long serialVersionUID=2323006706369304418L;
    @Override public void onClick(    AjaxRequestTarget target){
      if (startX == 1 || startX < 0) {
        startX=1;
        endX=mapDim;
      }
 else {
        startX--;
        endX--;
      }
      target.addComponent(gameMapContainer);
    }
  }
);
}