diff --git a/addons/cssresources/src/css-resource-panel.test.js b/addons/cssresources/src/css-resource-panel.test.js
new file mode 100644
index 00000000000..2d3353e7a1e
--- /dev/null
+++ b/addons/cssresources/src/css-resource-panel.test.js
@@ -0,0 +1,304 @@
+import React from 'react';
+import { configure, mount, shallow } from 'enzyme';
+import Adapter from 'enzyme-adapter-react-16';
+import { SyntaxHighlighter } from '@storybook/components';
+import { STORY_RENDERED } from '@storybook/core-events';
+import { EVENTS, PARAM_KEY } from './constants';
+import { CssResourcePanel } from './css-resource-panel.tsx';
+
+configure({
+  adapter: new Adapter(),
+});
+
+const defaultParameters = [
+  {
+    id: 'fake-css-id-1',
+    code: 'fake-css-code-1',
+    picked: true,
+  },
+  {
+    id: 'fake-css-id-2',
+    code: 'fake-css-code-2',
+    picked: false,
+  },
+];
+const newFakeParameters = [
+  {
+    id: 'new-fake-css-id-1',
+    code: 'new-fake-css-code-1',
+    picked: false,
+  },
+  {
+    id: 'new-fake-css-id-2',
+    code: 'new-fake-css-code-2',
+    picked: true,
+  },
+];
+const defaultProps = {
+  active: true,
+  api: {
+    emit: jest.fn(),
+    on: jest.fn(),
+    off: jest.fn(),
+    getParameters: jest.fn(() => defaultParameters),
+  },
+};
+
+const shallowNode = (props = defaultProps) => shallow(<CssResourcePanel {...props} />);
+const mountNode = (props = defaultProps) => mount(<CssResourcePanel {...props} />);
+
+describe('CSSResourcePanel', () => {
+  describe('constructor', () => {
+    const node = mountNode();
+
+    it('should initialize state', () => {
+      expect(node).toHaveState({ list: [], currentStoryId: '' });
+    });
+
+    it('should not render anything', () => {
+      expect(node).toBeEmptyRender();
+    });
+  });
+
+  describe('componentDidMount', () => {
+    let spy;
+
+    afterEach(() => {
+      spy.mockClear();
+    });
+
+    it('should execute when component is mounted', () => {
+      spy = jest.spyOn(CssResourcePanel.prototype, 'componentDidMount');
+      shallowNode();
+      expect(spy).toHaveBeenCalled();
+    });
+
+    it('should add STORY_RENDERED listener to the api', () => {
+      const apiAdd = jest.fn();
+      const node = shallowNode({
+        ...defaultProps,
+        api: {
+          ...defaultProps.api,
+          on: apiAdd,
+        },
+      });
+      const { onStoryChange } = node.instance();
+      expect(apiAdd).toHaveBeenCalledWith(STORY_RENDERED, onStoryChange);
+    });
+  });
+
+  describe('componentWillUnmount', () => {
+    let spy;
+
+    afterEach(() => {
+      if (spy) {
+        spy.mockClear();
+      }
+    });
+
+    it('should execute when component is unmounted', () => {
+      spy = jest.spyOn(CssResourcePanel.prototype, 'componentWillUnmount');
+      shallowNode().unmount();
+      expect(spy).toHaveBeenCalled();
+    });
+
+    it('should remove STORY_RENDERED listener from the api', () => {
+      const apiRemove = jest.fn();
+      const node = shallowNode({
+        ...defaultProps,
+        api: {
+          ...defaultProps.api,
+          off: apiRemove,
+        },
+      });
+      const { onStoryChange } = node.instance();
+      node.unmount();
+      expect(apiRemove).toHaveBeenCalledWith(STORY_RENDERED, onStoryChange);
+    });
+  });
+
+  describe('onStoryChange', () => {
+    it('should populate list with the default items', () => {
+      const node = shallowNode();
+      expect(node.state('list')).toMatchObject([]);
+      node.instance().onStoryChange('fake-story-id');
+      expect(node.state('list')).toMatchObject(defaultParameters);
+    });
+
+    it('should pull default items from getParameters', () => {
+      const apiGetParameters = jest.fn(() => newFakeParameters);
+      const node = shallowNode({
+        ...defaultProps,
+        api: {
+          ...defaultProps.api,
+          getParameters: apiGetParameters,
+        },
+      });
+      expect(node.state('list')).toMatchObject([]);
+      node.instance().onStoryChange('fake-story-id');
+      expect(apiGetParameters).toHaveBeenCalledWith('fake-story-id', PARAM_KEY);
+      expect(node.state('list')).toMatchObject(newFakeParameters);
+    });
+
+    it('should maintain picked attribute for matching ids', () => {
+      const node = shallowNode();
+      const invertedItem = {
+        ...defaultParameters[0],
+        picked: !defaultParameters[0].picked,
+      };
+      node.setState({ list: [invertedItem] });
+      node.instance().onStoryChange('fake-story-id');
+      expect(node.state('list')).toMatchObject([
+        {
+          ...defaultParameters[0],
+          picked: !defaultParameters[0].picked,
+        },
+        ...defaultParameters.slice(1),
+      ]);
+    });
+
+    it("should not overwrite list when story id hasn't changed", () => {
+      const fakeList = [];
+      const apiGetParameters = jest.fn(() => newFakeParameters);
+      const node = shallowNode({
+        ...defaultProps,
+        api: {
+          ...defaultProps.api,
+          getParameters: apiGetParameters,
+        },
+      });
+      node.setState({ list: fakeList, currentStoryId: 'fake-story-id' });
+      expect(node.state('list')).toEqual(fakeList);
+      node.instance().onStoryChange('fake-story-id');
+      expect(node.state('list')).toEqual(fakeList);
+    });
+
+    it('should not overwrite list when default list is undefined', () => {
+      const fakeList = [];
+      const apiGetParameters = jest.fn(() => undefined);
+      const node = shallowNode({
+        ...defaultProps,
+        api: {
+          ...defaultProps.api,
+          getParameters: apiGetParameters,
+        },
+      });
+      node.setState({ list: fakeList });
+      expect(node.state('list')).toEqual(fakeList);
+      node.instance().onStoryChange('fake-story-id');
+      expect(node.state('list')).toEqual(fakeList);
+    });
+  });
+
+  describe('onChange', () => {
+    let spy;
+
+    afterEach(() => {
+      if (spy) {
+        spy.mockClear();
+      }
+    });
+
+    const changedIndex = 1;
+    const fakeEvent = {
+      target: {
+        id: defaultParameters[changedIndex].id,
+        checked: true,
+      },
+    };
+    const newFakeList = defaultParameters.map((param, index) =>
+      index === changedIndex
+        ? {
+            ...param,
+            picked: true,
+          }
+        : param
+    );
+
+    it('should update the list with new picked items', () => {
+      const node = shallowNode();
+      node.instance().onStoryChange('fake-story-id');
+      node.instance().onChange(fakeEvent);
+      expect(node.state('list')).toMatchObject(newFakeList);
+    });
+
+    it('should call emit method with updated list', () => {
+      spy = jest.spyOn(CssResourcePanel.prototype, 'emit');
+      const node = shallowNode();
+      node.instance().onStoryChange('fake-story-id');
+      node.instance().onChange(fakeEvent);
+      expect(spy).toHaveBeenCalledWith(newFakeList);
+    });
+  });
+
+  describe('emit', () => {
+    it('should call emit from the api with EVENTS.SET', () => {
+      const apiEmit = jest.fn();
+      const node = shallowNode({
+        ...defaultProps,
+        api: {
+          ...defaultProps.api,
+          emit: apiEmit,
+        },
+      });
+      node.instance().emit(newFakeParameters);
+      expect(apiEmit).toHaveBeenCalledWith(EVENTS.SET, newFakeParameters);
+    });
+  });
+
+  describe('render', () => {
+    it('should not render anything when not active', () => {
+      const node = shallowNode({
+        ...defaultProps,
+        active: false,
+      });
+      node.instance().onStoryChange('fake-story-id');
+      expect(node).toBeEmptyRender();
+    });
+
+    describe('each list item', () => {
+      const node = shallowNode();
+      node.instance().onStoryChange('fake-story-id');
+
+      defaultParameters.forEach(param => {
+        it(`should render list item with id '${param.id}'`, () => {
+          expect(node.find(`#${param.id}`).length).toEqual(1);
+        });
+
+        it(`should render list item with id '${param.id}' as ${
+          param.picked ? 'checked' : 'unchecked'
+        }`, () => {
+          expect(
+            node
+              .find(`#${param.id}`)
+              .first()
+              .prop('checked')
+          ).toBe(param.picked);
+        });
+      });
+    });
+
+    it('should not render code for items without a code', () => {
+      const apiGetParameters = jest.fn(() => [
+        {
+          id: 'local-fake-id-1',
+          picked: true,
+        },
+        {
+          id: 'local-fake-id-2',
+          code: 'local-fake-code-2',
+          picked: false,
+        },
+      ]);
+      const node = shallowNode({
+        ...defaultProps,
+        api: {
+          ...defaultProps.api,
+          getParameters: apiGetParameters,
+        },
+      });
+      node.instance().onStoryChange('fake-story-id');
+      expect(node.find(SyntaxHighlighter).length).toEqual(1);
+    });
+  });
+});
diff --git a/addons/cssresources/src/css-resource-panel.tsx b/addons/cssresources/src/css-resource-panel.tsx
index 874b3620455..f1ba6c8618f 100644
--- a/addons/cssresources/src/css-resource-panel.tsx
+++ b/addons/cssresources/src/css-resource-panel.tsx
@@ -18,14 +18,20 @@ interface CssResourcePanelProps {
 }
 
 interface CssResourcePanelState {
+  currentStoryId: string;
   list: CssResource[];
 }
 
+interface CssResourceLookup {
+  [key: string]: CssResource;
+}
+
 export class CssResourcePanel extends Component<CssResourcePanelProps, CssResourcePanelState> {
   constructor(props: CssResourcePanelProps) {
     super(props);
 
     this.state = {
+      currentStoryId: '',
       list: [],
     };
   }
@@ -41,12 +47,26 @@ export class CssResourcePanel extends Component<CssResourcePanelProps, CssResour
   }
 
   onStoryChange = (id: string) => {
+    const { list: currentList, currentStoryId } = this.state;
     const { api } = this.props;
     const list = api.getParameters(id, PARAM_KEY) as CssResource[];
 
-    if (list) {
-      const picked = list.filter(res => res.picked);
-      this.setState({ list }, () => this.emit(picked));
+    if (list && currentStoryId !== id) {
+      const existingIds = currentList.reduce((lookup: CssResourceLookup, res) => {
+        lookup[res.id] = res;
+        return lookup;
+      }, {}) as CssResourceLookup;
+      const mergedList = list.map(res => {
+        const existingItem = existingIds[res.id];
+        return existingItem
+          ? {
+              ...res,
+              picked: existingItem.picked,
+            }
+          : res;
+      });
+      const picked = mergedList.filter(res => res.picked);
+      this.setState({ list: mergedList, currentStoryId: id }, () => this.emit(picked));
     }
   };
 
@@ -65,7 +85,7 @@ export class CssResourcePanel extends Component<CssResourcePanelProps, CssResour
   }
 
   render() {
-    const { list = [] } = this.state;
+    const { list } = this.state;
     const { active } = this.props;
 
     if (!active) {