Check for the selected sound before rendering the editor

src/containers/sound-tab.jsx

@@ -104,7 +104,7 @@ class SoundTab extends React.Component {
                 onDeleteClick={this.handleDeleteSound}
                 onItemClick={this.handleSelectSound}
             >
-                {sprite.sounds && sprite.sounds.length > 0 ? (
+                {sprite.sounds && sprite.sounds[this.state.selectedSoundIndex] ? (
                     <SoundEditor soundIndex={this.state.selectedSoundIndex} />
                 ) : null}
                 {this.props.soundRecorderVisible ? (