Remove shouldComponentUpdate from TargetPane

It doesn't help anything. Doing a deep compare is unnecessary because the underlying components will do the necessary comparison themselves. Simply seeing if the sprite list has changed at all is enough.

src/components/target-pane/target-pane.jsx

-const isEqual = require('lodash.isequal');
-const omit = require('lodash.omit');
 const classNames = require('classnames');
 const PropTypes = require('prop-types');
 const React = require('react');
@@ -23,119 +21,106 @@ const addIcon = require('./icon--add.svg');
  * @param {object} props Props for the component
  * @returns {React.Component} rendered component
  */
-class TargetPane extends React.Component {
-    shouldComponentUpdate (nextProps) {
-        return (
-            // Do a normal shallow compare on all props except sprites
-            Object.keys(omit(nextProps, ['sprites']))
-                .reduce((all, k) => all || nextProps[k] !== this.props[k], false) ||
-            // Deep compare on sprites object
-            !isEqual(this.props.sprites, nextProps.sprites)
-        );
-    }
-    render () {
-        const {
-            editingTarget,
-            backdropLibraryVisible,
-            costumeLibraryVisible,
-            soundLibraryVisible,
-            spriteLibraryVisible,
-            onChangeSpriteDirection,
-            onChangeSpriteName,
-            onChangeSpriteRotationStyle,
-            onChangeSpriteVisibility,
-            onChangeSpriteX,
-            onChangeSpriteY,
-            onDeleteSprite,
-            onNewSpriteClick,
-            onNewBackdropClick,
-            onRequestCloseBackdropLibrary,
-            onRequestCloseCostumeLibrary,
-            onRequestCloseSoundLibrary,
-            onRequestCloseSpriteLibrary,
-            onSelectSprite,
-            stage,
-            sprites,
-            vm,
-            ...componentProps
-        } = this.props;
-        return (
-            <Box
-                className={styles.targetPane}
-                {...componentProps}
-            >
+const TargetPane = ({
+    editingTarget,
+    backdropLibraryVisible,
+    costumeLibraryVisible,
+    soundLibraryVisible,
+    spriteLibraryVisible,
+    onChangeSpriteDirection,
+    onChangeSpriteName,
+    onChangeSpriteRotationStyle,
+    onChangeSpriteVisibility,
+    onChangeSpriteX,
+    onChangeSpriteY,
+    onDeleteSprite,
+    onNewSpriteClick,
+    onNewBackdropClick,
+    onRequestCloseBackdropLibrary,
+    onRequestCloseCostumeLibrary,
+    onRequestCloseSoundLibrary,
+    onRequestCloseSpriteLibrary,
+    onSelectSprite,
+    stage,
+    sprites,
+    vm,
+    ...componentProps
+}) => (
+    <Box
+        className={styles.targetPane}
+        {...componentProps}
+    >
 
-                <SpriteSelectorComponent
-                    selectedId={editingTarget}
-                    sprites={sprites}
-                    onChangeSpriteDirection={onChangeSpriteDirection}
-                    onChangeSpriteName={onChangeSpriteName}
-                    onChangeSpriteRotationStyle={onChangeSpriteRotationStyle}
-                    onChangeSpriteVisibility={onChangeSpriteVisibility}
-                    onChangeSpriteX={onChangeSpriteX}
-                    onChangeSpriteY={onChangeSpriteY}
-                    onDeleteSprite={onDeleteSprite}
-                    onSelectSprite={onSelectSprite}
-                />
-                <Box className={styles.stageSelectorWrapper}>
-                    {stage.id && <StageSelector
-                        backdropCount={stage.costumeCount}
-                        id={stage.id}
-                        selected={stage.id === editingTarget}
-                        url={
-                            stage.costume &&
-                            stage.costume.url
-                        }
-                        onSelect={onSelectSprite}
-                    />}
-                    <Box>
+        <SpriteSelectorComponent
+            selectedId={editingTarget}
+            sprites={sprites}
+            onChangeSpriteDirection={onChangeSpriteDirection}
+            onChangeSpriteName={onChangeSpriteName}
+            onChangeSpriteRotationStyle={onChangeSpriteRotationStyle}
+            onChangeSpriteVisibility={onChangeSpriteVisibility}
+            onChangeSpriteX={onChangeSpriteX}
+            onChangeSpriteY={onChangeSpriteY}
+            onDeleteSprite={onDeleteSprite}
+            onSelectSprite={onSelectSprite}
+        />
+        <Box className={styles.stageSelectorWrapper}>
+            {stage.id && <StageSelector
+                assetId={
+                    stage.costume &&
+                    stage.costume.assetId
+                }
+                backdropCount={stage.costumeCount}
+                id={stage.id}
+                selected={stage.id === editingTarget}
+                onSelect={onSelectSprite}
+            />}
+            <Box>
 
-                        <button
-                            className={classNames(styles.addButtonWrapper, styles.addButtonWrapperSprite)}
-                            onClick={onNewSpriteClick}
-                        >
-                            <img
-                                className={styles.addButton}
-                                src={addIcon}
-                            />
-                        </button>
+                <button
+                    className={classNames(styles.addButtonWrapper, styles.addButtonWrapperSprite)}
+                    onClick={onNewSpriteClick}
+                >
+                    <img
+                        className={styles.addButton}
+                        src={addIcon}
+                    />
+                </button>
 
-                        <button
-                            className={classNames(styles.addButtonWrapper, styles.addButtonWrapperStage)}
-                            onClick={onNewBackdropClick}
-                        >
-                            <img
-                                className={styles.addButton}
-                                src={addIcon}
-                            />
-                        </button>
+                <button
+                    className={classNames(styles.addButtonWrapper, styles.addButtonWrapperStage)}
+                    onClick={onNewBackdropClick}
+                >
+                    <img
+                        className={styles.addButton}
+                        src={addIcon}
+                    />
+                </button>
 
-                        <SpriteLibrary
-                            visible={spriteLibraryVisible}
-                            vm={vm}
-                            onRequestClose={onRequestCloseSpriteLibrary}
-                        />
-                        <CostumeLibrary
-                            visible={costumeLibraryVisible}
-                            vm={vm}
-                            onRequestClose={onRequestCloseCostumeLibrary}
-                        />
-                        <SoundLibrary
-                            visible={soundLibraryVisible}
-                            vm={vm}
-                            onRequestClose={onRequestCloseSoundLibrary}
-                        />
-                        <BackdropLibrary
-                            visible={backdropLibraryVisible}
-                            vm={vm}
-                            onRequestClose={onRequestCloseBackdropLibrary}
-                        />
-                    </Box>
-                </Box>
+                <SpriteLibrary
+                    visible={spriteLibraryVisible}
+                    vm={vm}
+                    onRequestClose={onRequestCloseSpriteLibrary}
+                />
+                <CostumeLibrary
+                    visible={costumeLibraryVisible}
+                    vm={vm}
+                    onRequestClose={onRequestCloseCostumeLibrary}
+                />
+                <SoundLibrary
+                    visible={soundLibraryVisible}
+                    vm={vm}
+                    onRequestClose={onRequestCloseSoundLibrary}
+                />
+                <BackdropLibrary
+                    visible={backdropLibraryVisible}
+                    vm={vm}
+                    onRequestClose={onRequestCloseBackdropLibrary}
+                />
             </Box>
-        );
-    }
-}
+        </Box>
+    </Box>
+);
+
 const spriteShape = PropTypes.shape({
     costume: PropTypes.shape({
         url: PropTypes.string,