private void stopResizing() {
        if (glassElem != null) {
            final Element parent = glassElem.getParentElement();
            if (parent != null) {
                parent.removeChild(glassElem);
            }
        }
        isResizing = false;
        onResize();
    }
Sets the minimum allowable size for the given widget.
<p>
<p>
Its associated splitter cannot be dragged to a position that would make
it smaller than this size. This method has no effect for the
{@link DockLayoutPanel.Direction#CENTER} widget.
</p>

@param child   the child whose minimum size will be set
@param minSize the minimum size for this widget
stroom-core-client-widget/src/main/java/com/google/gwt/user/client/ui/MySplitLayoutPanel.java