Scroll to extension category when attempting to load duplicate

src/containers/blocks.jsx

@@ -31,6 +31,7 @@ class Blocks extends React.Component {
         bindAll(this, [
             'attachVM',
             'detachVM',
+            'handleCategorySelected',
             'handlePromptStart',
             'handlePromptCallback',
             'handlePromptClose',
@@ -194,6 +195,9 @@ class Blocks extends React.Component {
         const toolboxXML = makeToolboxXML(dynamicBlocksXML);
         this.props.onExtensionAdded(toolboxXML);
         const categoryName = blocksInfo[0].json.category;
+        this.handleCategorySelected(categoryName);
+    }
+    handleCategorySelected (categoryName) {
         this.workspace.toolbox_.setSelectedCategoryByName(categoryName);
     }
     setBlocks (blocks) {
@@ -241,6 +245,7 @@ class Blocks extends React.Component {
                 {extensionLibraryVisible ? (
                     <ExtensionLibrary
                         vm={vm}
+                        onCategorySelected={this.handleCategorySelected}
                         onRequestClose={onRequestCloseExtensionLibrary}
                     />
                 ) : null}

src/containers/extension-library.jsx

@@ -20,9 +20,10 @@ class ExtensionLibrary extends React.PureComponent {
         const url = item.extensionURL || prompt('Enter the URL of the extension');
         if (url) {
             if (this.props.vm.extensionManager.isExtensionLoaded(url)) {
-                return;
+                this.props.onCategorySelected(item.name);
+            } else {
+                this.props.vm.extensionManager.loadExtensionURL(url);
             }
-            this.props.vm.extensionManager.loadExtensionURL(url);
         }
     }
     render () {
@@ -43,6 +44,7 @@ class ExtensionLibrary extends React.PureComponent {
 }
 
 ExtensionLibrary.propTypes = {
+    onCategorySelected: PropTypes.func,
     onRequestClose: PropTypes.func,
     visible: PropTypes.bool,
     vm: PropTypes.instanceOf(VM).isRequired // eslint-disable-line react/no-unused-prop-types