diff --git a/__tests__/src/components/WorkspaceMosaic.test.js b/__tests__/src/components/WorkspaceMosaic.test.js
index e89f5aa6f9..ed15fe9f8a 100644
--- a/__tests__/src/components/WorkspaceMosaic.test.js
+++ b/__tests__/src/components/WorkspaceMosaic.test.js
@@ -76,7 +76,11 @@ describe('WorkspaceMosaic', () => {
       });
     });
     it('by default use workspace.layout', () => {
-      wrapper = createWrapper({ windows: {}, workspace: { layout: 'foo' } });
+      wrapper = createWrapper({ windows: { foo: 'bar' }, workspace: { layout: 'foo' } });
+      expect(wrapper.instance().determineWorkspaceLayout()).toEqual('foo');
+    });
+    it('generates a new layout if windows do not match current layout', () => {
+      wrapper = createWrapper({ windows: { foo: 'bar' }, workspace: { layout: { first: 'foo', second: 'bark' } } });
       expect(wrapper.instance().determineWorkspaceLayout()).toEqual('foo');
     });
     it('when window ids match workspace layout', () => {
diff --git a/src/components/WorkspaceMosaic.js b/src/components/WorkspaceMosaic.js
index 62381b5326..b33a6a3637 100644
--- a/src/components/WorkspaceMosaic.js
+++ b/src/components/WorkspaceMosaic.js
@@ -91,7 +91,11 @@ export class WorkspaceMosaic extends React.Component {
       layout.addWindows(addedWindows);
       return layout.layout;
     }
-
+    // Windows were removed (perhaps in a different Workspace). We don't have a
+    // way to reconfigure.. so we have to random generate
+    if (!leaveKeys.every(e => sortedWindows.includes(e))) {
+      return createBalancedTreeFromLeaves(sortedWindows);
+    }
     return workspace.layout;
   }