Give GUIComponent responsibility of children

This will allow the GUIComponent to have control over the layout

src/components/gui/gui.jsx

+const defaultsDeep = require('lodash.defaultsdeep');
 const React = require('react');
+const VM = require('scratch-vm');
+
+const MediaLibrary = require('../../lib/media-library');
+const shapeFromPropTypes = require('../../lib/shape-from-prop-types');
+
+const Blocks = require('../../containers/blocks.jsx');
+const GreenFlag = require('../../containers/green-flag.jsx');
+const TargetPane = require('../../containers/target-pane.jsx');
+const Stage = require('../../containers/stage.jsx');
+const StopAll = require('../../containers/stop-all.jsx');
 
 const styles = require('./gui.css');
 
-const GUIComponent = props => (
-    <div className={styles.gui}>
-        {props.children}
-    </div>
-);
+const GUIComponent = props => {
+    let {
+        basePath,
+        blocksProps,
+        children,
+        greenFlagProps,
+        mediaLibrary,
+        targetPaneProps,
+        stageProps,
+        stopAllProps,
+        vm
+    } = props;
+    blocksProps = defaultsDeep({}, blocksProps, {
+        options: {
+            media: `${basePath}static/blocks-media/`
+        }
+    });
+    if (children) {
+        return (
+            <div className={styles.gui}>
+                {children}
+            </div>
+        );
+    }
+    return (
+        <div className={styles.gui}>
+            <GreenFlag
+                vm={vm}
+                {...greenFlagProps}
+            />
+            <StopAll
+                vm={vm}
+                {...stopAllProps}
+            />
+            <Stage
+                vm={vm}
+                {...stageProps}
+            />
+            <TargetPane
+                mediaLibrary={mediaLibrary}
+                vm={vm}
+                {... targetPaneProps}
+            />
+            <Blocks
+                vm={vm}
+                {... blocksProps}
+            />
+        </div>
+    );
+};
 
 GUIComponent.propTypes = {
-    children: React.PropTypes.node
+    basePath: React.PropTypes.string,
+    blocksProps: shapeFromPropTypes(Blocks.propTypes, {omit: ['vm']}),
+    children: React.PropTypes.node,
+    greenFlagProps: shapeFromPropTypes(GreenFlag.propTypes, {omit: ['vm']}),
+    mediaLibrary: React.PropTypes.instanceOf(MediaLibrary),
+    stageProps: shapeFromPropTypes(Stage.propTypes, {omit: ['vm']}),
+    stopAllProps: shapeFromPropTypes(StopAll.propTypes, {omit: ['vm']}),
+    targetPaneProps: shapeFromPropTypes(TargetPane.propTypes, {omit: ['vm']}),
+    vm: React.PropTypes.instanceOf(VM)
+};
+
+GUIComponent.defaultProps = {
+    basePath: '/',
+    blocksProps: {},
+    greenFlagProps: {},
+    mediaLibrary: new MediaLibrary(),
+    targetPaneProps: {},
+    stageProps: {},
+    stopAllProps: {},
+    vm: new VM()
 };
 
 module.exports = GUIComponent;

src/containers/gui.jsx

-const defaultsDeep = require('lodash.defaultsdeep');
 const React = require('react');
 const VM = require('scratch-vm');
 
-const MediaLibrary = require('../lib/media-library');
-const shapeFromPropTypes = require('../lib/shape-from-prop-types');
 const vmListenerHOC = require('../lib/vm-listener-hoc.jsx');
 
-const Blocks = require('./blocks.jsx');
 const GUIComponent = require('../components/gui/gui.jsx');
-const GreenFlag = require('./green-flag.jsx');
-const TargetPane = require('./target-pane.jsx');
-const Stage = require('./stage.jsx');
-const StopAll = require('./stop-all.jsx');
 
 class GUI extends React.Component {
     componentDidMount () {
@@ -27,80 +19,26 @@ class GUI extends React.Component {
         this.props.vm.stopAll();
     }
     render () {
-        let {
-            basePath,
-            blocksProps,
-            greenFlagProps,
-            mediaLibrary,
+        const {
             projectData, // eslint-disable-line no-unused-vars
-            targetPaneProps,
-            stageProps,
-            stopAllProps,
             vm,
-            ...guiProps
+            ...componentProps
         } = this.props;
-        blocksProps = defaultsDeep({}, blocksProps, {
-            options: {
-                media: `${basePath}static/blocks-media/`
-            }
-        });
-        if (this.props.children) {
-            return (
-                <GUIComponent {... guiProps}>
-                    {this.props.children}
-                </GUIComponent>
-            );
-        }
         return (
-            <GUIComponent {... guiProps}>
-                <GreenFlag
-                    vm={vm}
-                    {...greenFlagProps}
-                />
-                <StopAll
-                    vm={vm}
-                    {...stopAllProps}
-                />
-                <Stage
-                    vm={vm}
-                    {...stageProps}
-                />
-                <TargetPane
-                    mediaLibrary={mediaLibrary}
-                    vm={vm}
-                    {... targetPaneProps}
-                />
-                <Blocks
-                    vm={vm}
-                    {... blocksProps}
-                />
-            </GUIComponent>
+            <GUIComponent
+                vm={vm}
+                {...componentProps}
+            />
         );
     }
 }
 
 GUI.propTypes = {
-    basePath: React.PropTypes.string,
-    blocksProps: shapeFromPropTypes(Blocks.propTypes, {omit: ['vm']}),
-    children: React.PropTypes.node,
-    greenFlagProps: shapeFromPropTypes(GreenFlag.propTypes, {omit: ['vm']}),
-    mediaLibrary: React.PropTypes.instanceOf(MediaLibrary),
+    ...GUIComponent.propTypes,
     projectData: React.PropTypes.string,
-    stageProps: shapeFromPropTypes(Stage.propTypes, {omit: ['vm']}),
-    stopAllProps: shapeFromPropTypes(StopAll.propTypes, {omit: ['vm']}),
-    targetPaneProps: shapeFromPropTypes(TargetPane.propTypes, {omit: ['vm']}),
     vm: React.PropTypes.instanceOf(VM)
 };
 
-GUI.defaultProps = {
-    basePath: '/',
-    blocksProps: {},
-    greenFlagProps: {},
-    mediaLibrary: new MediaLibrary(),
-    targetPaneProps: {},
-    stageProps: {},
-    stopAllProps: {},
-    vm: new VM()
-};
+GUI.defaultProps = GUIComponent.defaultProps;
 
 module.exports = vmListenerHOC(GUI);