diff --git a/crates/collab/src/tests.rs b/crates/collab/src/tests.rs
index 8949b60993..80df0ed6df 100644
--- a/crates/collab/src/tests.rs
+++ b/crates/collab/src/tests.rs
@@ -197,8 +197,8 @@ impl TestServer {
             fs: fs.clone(),
             build_window_options: |_, _, _| Default::default(),
             initialize_workspace: |_, _, _| unimplemented!(),
-            dock_default_item_factory: |_, _| unimplemented!(),
-            background_actions: || unimplemented!(),
+            dock_default_item_factory: |_, _| None,
+            background_actions: || &[],
         });
 
         Project::init(&client);
diff --git a/crates/editor/src/editor_tests.rs b/crates/editor/src/editor_tests.rs
index 0176a1e01b..d73c3c87db 100644
--- a/crates/editor/src/editor_tests.rs
+++ b/crates/editor/src/editor_tests.rs
@@ -484,9 +484,7 @@ fn test_navigation_history(cx: &mut gpui::MutableAppContext) {
     cx.set_global(Settings::test(cx));
     cx.set_global(DragAndDrop::<Workspace>::default());
     use workspace::item::Item;
-    let (_, pane) = cx.add_window(Default::default(), |cx| {
-        Pane::new(0, None, || unimplemented!(), cx)
-    });
+    let (_, pane) = cx.add_window(Default::default(), |cx| Pane::new(0, None, || &[], cx));
     let buffer = MultiBuffer::build_simple(&sample_text(300, 5, 'a'), cx);
 
     cx.add_view(&pane, |cx| {
@@ -2356,10 +2354,10 @@ async fn test_clipboard(cx: &mut gpui::TestAppContext) {
         e.handle_input(") ", cx);
     });
     cx.assert_editor_state(indoc! {"
-        ( one✅
-        three
-        five ) ˇtwo one✅ four three six five ( one✅
-        three
+        ( one✅ 
+        three 
+        five ) ˇtwo one✅ four three six five ( one✅ 
+        three 
         five ) ˇ"});
 
     // Cut with three selections, one of which is full-line.
@@ -5564,7 +5562,7 @@ async fn test_following_with_multiple_excerpts(cx: &mut gpui::TestAppContext) {
     Settings::test_async(cx);
     let fs = FakeFs::new(cx.background());
     let project = Project::test(fs, ["/file.rs".as_ref()], cx).await;
-    let (_, pane) = cx.add_window(|cx| Pane::new(0, None, || unimplemented!(), cx));
+    let (_, pane) = cx.add_window(|cx| Pane::new(0, None, || &[], cx));
 
     let leader = pane.update(cx, |_, cx| {
         let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
diff --git a/crates/workspace/src/dock.rs b/crates/workspace/src/dock.rs
index efba568b90..fd7638c5fb 100644
--- a/crates/workspace/src/dock.rs
+++ b/crates/workspace/src/dock.rs
@@ -500,7 +500,7 @@ mod tests {
                 0,
                 project.clone(),
                 default_item_factory,
-                || unimplemented!(),
+                || &[],
                 cx,
             )
         });
@@ -634,7 +634,7 @@ mod tests {
                     0,
                     project,
                     default_item_factory,
-                    || unimplemented!(),
+                    || &[],
                     cx,
                 )
             });
diff --git a/crates/workspace/src/workspace.rs b/crates/workspace/src/workspace.rs
index 40053b103a..ef14bfa2fe 100644
--- a/crates/workspace/src/workspace.rs
+++ b/crates/workspace/src/workspace.rs
@@ -455,8 +455,8 @@ impl AppState {
             user_store,
             initialize_workspace: |_, _, _| {},
             build_window_options: |_, _, _| Default::default(),
-            dock_default_item_factory: |_, _| unimplemented!(),
-            background_actions: || unimplemented!(),
+            dock_default_item_factory: |_, _| None,
+            background_actions: || &[],
         })
     }
 }
@@ -3017,8 +3017,8 @@ mod tests {
                 Default::default(),
                 0,
                 project.clone(),
-                |_, _| unimplemented!(),
-                || unimplemented!(),
+                |_, _| None,
+                || &[],
                 cx,
             )
         });
@@ -3090,8 +3090,8 @@ mod tests {
                 Default::default(),
                 0,
                 project.clone(),
-                |_, _| unimplemented!(),
-                || unimplemented!(),
+                |_, _| None,
+                || &[],
                 cx,
             )
         });
@@ -3191,8 +3191,8 @@ mod tests {
                 Default::default(),
                 0,
                 project.clone(),
-                |_, _| unimplemented!(),
-                || unimplemented!(),
+                |_, _| None,
+                || &[],
                 cx,
             )
         });
@@ -3231,14 +3231,7 @@ mod tests {
 
         let project = Project::test(fs, None, cx).await;
         let (window_id, workspace) = cx.add_window(|cx| {
-            Workspace::new(
-                Default::default(),
-                0,
-                project,
-                |_, _| unimplemented!(),
-                || unimplemented!(),
-                cx,
-            )
+            Workspace::new(Default::default(), 0, project, |_, _| None, || &[], cx)
         });
 
         let item1 = cx.add_view(&workspace, |cx| {
@@ -3347,14 +3340,7 @@ mod tests {
 
         let project = Project::test(fs, [], cx).await;
         let (window_id, workspace) = cx.add_window(|cx| {
-            Workspace::new(
-                Default::default(),
-                0,
-                project,
-                |_, _| unimplemented!(),
-                || unimplemented!(),
-                cx,
-            )
+            Workspace::new(Default::default(), 0, project, |_, _| None, || &[], cx)
         });
 
         // Create several workspace items with single project entries, and two
@@ -3463,14 +3449,7 @@ mod tests {
 
         let project = Project::test(fs, [], cx).await;
         let (window_id, workspace) = cx.add_window(|cx| {
-            Workspace::new(
-                Default::default(),
-                0,
-                project,
-                |_, _| unimplemented!(),
-                || unimplemented!(),
-                cx,
-            )
+            Workspace::new(Default::default(), 0, project, |_, _| None, || &[], cx)
         });
 
         let item = cx.add_view(&workspace, |cx| {
@@ -3589,14 +3568,7 @@ mod tests {
 
         let project = Project::test(fs, [], cx).await;
         let (_, workspace) = cx.add_window(|cx| {
-            Workspace::new(
-                Default::default(),
-                0,
-                project,
-                |_, _| unimplemented!(),
-                || unimplemented!(),
-                cx,
-            )
+            Workspace::new(Default::default(), 0, project, |_, _| None, || &[], cx)
         });
 
         let item = cx.add_view(&workspace, |cx| {