reproduce sigma.js parent container resize issue. This is basic.html w/ minor mods.

basic_with_resize_issue.html

<!-- START SIGMA IMPORTS -->
<script src="../src/sigma.core.js"></script>
<script src="../src/conrad.js"></script>
<script src="../src/utils/sigma.utils.js"></script>
<script src="../src/utils/sigma.polyfills.js"></script>
<script src="../src/sigma.settings.js"></script>
<script src="../src/classes/sigma.classes.dispatcher.js"></script>
<script src="../src/classes/sigma.classes.configurable.js"></script>
<script src="../src/classes/sigma.classes.graph.js"></script>
<script src="../src/classes/sigma.classes.camera.js"></script>
<script src="../src/classes/sigma.classes.quad.js"></script>
<script src="../src/captors/sigma.captors.mouse.js"></script>
<script src="../src/captors/sigma.captors.touch.js"></script>
<script src="../src/renderers/sigma.renderers.canvas.js"></script>
<script src="../src/renderers/sigma.renderers.webgl.js"></script>
<script src="../src/renderers/sigma.renderers.def.js"></script>
<script src="../src/renderers/webgl/sigma.webgl.nodes.def.js"></script>
<script src="../src/renderers/webgl/sigma.webgl.nodes.fast.js"></script>
<script src="../src/renderers/webgl/sigma.webgl.edges.def.js"></script>
<script src="../src/renderers/webgl/sigma.webgl.edges.fast.js"></script>
<script src="../src/renderers/webgl/sigma.webgl.edges.arrow.js"></script>
<script src="../src/renderers/canvas/sigma.canvas.labels.def.js"></script>
<script src="../src/renderers/canvas/sigma.canvas.hovers.def.js"></script>
<script src="../src/renderers/canvas/sigma.canvas.nodes.def.js"></script>
<script src="../src/renderers/canvas/sigma.canvas.edges.def.js"></script>
<script src="../src/renderers/canvas/sigma.canvas.edges.curve.js"></script>
<script src="../src/renderers/canvas/sigma.canvas.edges.arrow.js"></script>
<script src="../src/renderers/canvas/sigma.canvas.edges.curvedArrow.js"></script>
<script src="../src/middlewares/sigma.middlewares.rescale.js"></script>
<script src="../src/middlewares/sigma.middlewares.copy.js"></script>
<script src="../src/misc/sigma.misc.animation.js"></script>
<script src="../src/misc/sigma.misc.bindEvents.js"></script>
<script src="../src/misc/sigma.misc.drawHovers.js"></script>
<!-- END SIGMA IMPORTS -->
<div id="container">
    <style>
        #graph-container {

/*===================================*/
/*===================================*/
/*===================================*/
/* MODIFIED*/
/*===================================*/
/*===================================*/
/*===================================*/

            width: 800px;
            height: 800px;
            border: 1px solid black;
        }
    </style>
    <div id="graph-container"></div>
</div>
<script>
    /**
     * This is a basic example on how to instantiate sigma. A random graph is
     * generated and stored in the "graph" variable, and then sigma is instantiated
     * directly with the graph.
     *
     * The simple instance of sigma is enough to make it render the graph on the on
     * the screen, since the graph is given directly to the constructor.
     */
    var i,
            s,
            N = 100,
            E = 500,
            g = {
                nodes: [],
                edges: []
            };

    // Generate a random graph:
    for (i = 0; i < N; i++)
        g.nodes.push({
            id: 'n' + i,
            label: 'Node ' + i,
            x: Math.random(),
            y: Math.random(),
            size: Math.random(),
            color: '#666'
        });

    for (i = 0; i < E; i++)
        g.edges.push({
            id: 'e' + i,
            source: 'n' + (Math.random() * N | 0),
            target: 'n' + (Math.random() * N | 0),
            size: Math.random(),
            color: '#ccc'
        });

    // Instantiate sigma:
    s = new sigma({
        graph: g,
        container: 'graph-container'
    });


/*===================================*/
/*===================================*/
/*===================================*/
/* MODIFIED*/
/*===================================*/
/*===================================*/
/*===================================*/

    setTimeout(function () {
        document.getElementById('graph-container').style.width = '400px';
        document.getElementById('graph-container').style.height = '400px';
        // Turning this on causes the graph to resize correctly
        // s.renderers[0].resize();
        s.refresh();
    }, 3000);

</script>