public void movingElements()
{
    //gets the new filler height to compare
    int newFillerHeight = getFiller().getHeight();

    //chapter contains an array of pages I need to deal with here
    Chapter chapter = getChapter();

    //element removed/shrunk
    //compares the oldFillerHeight which contains the height of the filler
    //prior to this particular resizing
    else if (newFillerHeight >= oldFillerHeight)
    {
            //fetches the next and previous page of this page (getPage()
            //returns page we are dealing with)
        Page previousPage = chapter.getPreviousPage(getPage());
        Page nextPage = chapter.getNextPage(getPage());

            //here is where it gets tricky
            //I didn't want to check if first (few) element(s) can be
            //moved to previous page (which can happen if the first, large
            //element followed by several small ones is removed) (CHECK A) AND
            //if any elements on the next page can be moved to this one
            //(CHECK B). What I did instead was to always do the CHECK A.

            //if this is the first page of the chapter, I cannot perform the
            //CHECK A
        if (previousPage == null)
        {
                    //I have to invoke this method on the next page, if it
                    //exists. If it doesn't, then this is the only page of
                    //the chapter and I have nothing to do here.
            if (nextPage != null)
            {
                            //this is explained bellow this method
                nextPage.dummy.setVisible(true);
            }
        }

            //if previous page exists, we preform CHECK A
        else
        {
            Element mover = getElement(1);

                    //I have to check if the first element on this page fits
                    //onto the free space of the previous one
                    //-2 is required to prevent infinite loops
            if (mover.getHeight() < previousPage.getFiller().getHeight()-2)
            {
                            //I move the element
                removeElement(mover);
                previousPage.addElement(mover, previousPage.getElementCount()+1);

                            //This is a flag that tells that an object was
                            //moved, you'll se why I need it soon enough
                chapter.setMoved(true);
            }

                    //If I can't move the object, I have move onto the next
                    //page (if it exists) and repeat the process. I also
                    //check for isMoved flag because maybe nothing was moved
                    //on the previous page and there is no need to keep the
                    //this chain of execution going
            else if ((nextPage != null) && (chapter.isMoved()))
            {
                            //sets isMoved flag to false so the above code
                            //would work
                            chapter.setMoved(false);
                nextPage.dummy.setVisible(true);
            }
        }
    }

    //saves the new filer height for further use
    oldFillerHeight = newFillerHeight;
}

dummy = new JPanel();
dummy.setVisible(false);

dummy.addComponentListener(new ComponentAdapter()
{
    @Override
    public void componentShown(ComponentEvent arg0)
    {
            dummy.setVisible(false);
        movingElements();
    }
});

filler.addComponentListener(new ComponentAdapter()
    {
        @Override
        public void componentResized(ComponentEvent arg0)
        {
            if (!getChapter().isChaining())
            {
                getChapter().setChaining(true);
                movingElements();
            }

            oldFillerHeight = getFiller().getHeight();
        }
    });

dummy.addComponentListener(new ComponentAdapter()
    {
        @Override
        public void componentShown(ComponentEvent arg0)
        {
            dummy.setVisible(false);
            movingElements();
        }
    });

public void movingElements()
{
    int newFillerHeight = getFiller().getHeight();
    Document document = getDocument();
    Chapter chapter = getChapter();

    //element added/enlarged
    if (newFillerHeight == 0)
    {
        Page nextPage = chapter.getNextPage(getPage());

        if (nextPage == null)
        {
            nextPage = new Page();
            chapter.addPage(nextPage, chapter.getPageIndex(getPage())+1);
        }

        Element mover = getPage().getElement(getPage().getElementCount());

        removeElement(mover);
        nextPage.addElement(mover, 1);

        getPage().dummy.setVisible(true);
    }

    //element removed/shrunk
    else if (newFillerHeight >= oldFillerHeight)
    {
        Page previousPage = chapter.getPreviousPage(getPage());
        Page nextPage = chapter.getNextPage(getPage());

        if (previousPage == null)
        {
            if (nextPage != null)
            {
                nextPage.dummy.setVisible(true);
            }

            else
            {
                //chain end
                chapter.setChaining(false);
            }
        }

        else
        {
            Element mover = getElement(1);

            if (mover.getHeight() < previousPage.getFiller().getHeight()-2)  //-2 is required to prevent infinite loops
            {
                removeElement(mover);
                previousPage.addElement(mover, previousPage.getElementCount()+1);

                chapter.setMoved(true);

                getPage().dummy.setVisible(true);
            }

            else if ((nextPage != null) && (chapter.isMoved()))
            {
                nextPage.dummy.setVisible(true);
            }

            else
            {
                //chain end
                chapter.setChaining(false);
            }
        }
    }

    else
    {
        //chain end
        chapter.setChaining(false);
    }
}

private AtomicBoolean chaining= new AtomicBoolean(false);

public boolean isChaining()
{
    return chaining.get();
}

public void setChaining(boolean chaining)
{
    this.chaining.set(chaining);
}