diff --git a/assets/keymaps/default-windows.json b/assets/keymaps/default-windows.json
index fc70ed68217f3520d0b8ac6aeb3affc82664d818..c0412152d70790ad89bcf1374cb315affb8fce36 100644
--- a/assets/keymaps/default-windows.json
+++ b/assets/keymaps/default-windows.json
@@ -134,7 +134,7 @@
       "ctrl-k z": "editor::ToggleSoftWrap",
       "ctrl-f": "buffer_search::Deploy",
       "ctrl-h": "buffer_search::DeployReplace",
-      "ctrl-shift-.": "assistant::QuoteSelection",
+      "ctrl-shift-.": "agent::QuoteSelection",
       "ctrl-shift-,": "assistant::InsertIntoEditor",
       "shift-alt-e": "editor::SelectEnclosingSymbol",
       "ctrl-shift-backspace": "editor::GoToPreviousChange",
@@ -244,7 +244,7 @@
       "ctrl-shift-i": "agent::ToggleOptionsMenu",
       // "ctrl-shift-alt-n": "agent::ToggleNewThreadMenu",
       "shift-alt-escape": "agent::ExpandMessageEditor",
-      "ctrl-shift-.": "assistant::QuoteSelection",
+      "ctrl-shift-.": "agent::QuoteSelection",
       "shift-alt-e": "agent::RemoveAllContext",
       "ctrl-shift-e": "project_panel::ToggleFocus",
       "ctrl-shift-enter": "agent::ContinueThread",
diff --git a/crates/agent_ui/src/acp/message_editor.rs b/crates/agent_ui/src/acp/message_editor.rs
index b7521517575a9831635f5e08a954c0e2bd493a80..626c9f3bb7bc3d9c146f584bb9acbc999c25c879 100644
--- a/crates/agent_ui/src/acp/message_editor.rs
+++ b/crates/agent_ui/src/acp/message_editor.rs
@@ -1030,6 +1030,7 @@ impl MessageEditor {
         ) else {
             return;
         };
+
         self.editor.update(cx, |message_editor, cx| {
             message_editor.edit([(cursor_anchor..cursor_anchor, completion.new_text)], cx);
         });
diff --git a/crates/agent_ui/src/acp/thread_view.rs b/crates/agent_ui/src/acp/thread_view.rs
index 07a2366f989bb1cf454b4dc2ab3c99b7da0ad528..8b8f127764ad36a9fb9afa029b22b2a113991d34 100644
--- a/crates/agent_ui/src/acp/thread_view.rs
+++ b/crates/agent_ui/src/acp/thread_view.rs
@@ -4972,10 +4972,12 @@ impl AcpThreadView {
         })
     }
 
+    /// Inserts the selected text into the message editor or the message being
+    /// edited, if any.
     pub(crate) fn insert_selections(&self, window: &mut Window, cx: &mut Context<Self>) {
-        self.message_editor.update(cx, |message_editor, cx| {
-            message_editor.insert_selections(window, cx);
-        })
+        self.active_editor(cx).update(cx, |editor, cx| {
+            editor.insert_selections(window, cx);
+        });
     }
 
     fn render_thread_retry_status_callout(
@@ -5386,6 +5388,23 @@ impl AcpThreadView {
         };
         task.detach_and_log_err(cx);
     }
+
+    /// Returns the currently active editor, either for a message that is being
+    /// edited or the editor for a new message.
+    fn active_editor(&self, cx: &App) -> Entity<MessageEditor> {
+        if let Some(index) = self.editing_message
+            && let Some(editor) = self
+                .entry_view_state
+                .read(cx)
+                .entry(index)
+                .and_then(|e| e.message_editor())
+                .cloned()
+        {
+            editor
+        } else {
+            self.message_editor.clone()
+        }
+    }
 }
 
 fn loading_contents_spinner(size: IconSize) -> AnyElement {
@@ -5400,7 +5419,7 @@ impl Focusable for AcpThreadView {
     fn focus_handle(&self, cx: &App) -> FocusHandle {
         match self.thread_state {
             ThreadState::Loading { .. } | ThreadState::Ready { .. } => {
-                self.message_editor.focus_handle(cx)
+                self.active_editor(cx).focus_handle(cx)
             }
             ThreadState::LoadError(_) | ThreadState::Unauthenticated { .. } => {
                 self.focus_handle.clone()
@@ -6661,4 +6680,146 @@ pub(crate) mod tests {
             )
         });
     }
+
+    #[gpui::test]
+    async fn test_message_editing_insert_selections(cx: &mut TestAppContext) {
+        init_test(cx);
+
+        let connection = StubAgentConnection::new();
+        connection.set_next_prompt_updates(vec![acp::SessionUpdate::AgentMessageChunk {
+            content: acp::ContentBlock::Text(acp::TextContent {
+                text: "Response".into(),
+                annotations: None,
+                meta: None,
+            }),
+        }]);
+
+        let (thread_view, cx) = setup_thread_view(StubAgentServer::new(connection), cx).await;
+        add_to_workspace(thread_view.clone(), cx);
+
+        let message_editor = cx.read(|cx| thread_view.read(cx).message_editor.clone());
+        message_editor.update_in(cx, |editor, window, cx| {
+            editor.set_text("Original message to edit", window, cx)
+        });
+        thread_view.update_in(cx, |thread_view, window, cx| thread_view.send(window, cx));
+        cx.run_until_parked();
+
+        let user_message_editor = thread_view.read_with(cx, |thread_view, cx| {
+            thread_view
+                .entry_view_state
+                .read(cx)
+                .entry(0)
+                .expect("Should have at least one entry")
+                .message_editor()
+                .expect("Should have message editor")
+                .clone()
+        });
+
+        cx.focus(&user_message_editor);
+        thread_view.read_with(cx, |thread_view, _cx| {
+            assert_eq!(thread_view.editing_message, Some(0));
+        });
+
+        // Ensure to edit the focused message before proceeding otherwise, since
+        // its content is not different from what was sent, focus will be lost.
+        user_message_editor.update_in(cx, |editor, window, cx| {
+            editor.set_text("Original message to edit with ", window, cx)
+        });
+
+        // Create a simple buffer with some text so we can create a selection
+        // that will then be added to the message being edited.
+        let (workspace, project) = thread_view.read_with(cx, |thread_view, _cx| {
+            (thread_view.workspace.clone(), thread_view.project.clone())
+        });
+        let buffer = project.update(cx, |project, cx| {
+            project.create_local_buffer("let a = 10 + 10;", None, false, cx)
+        });
+
+        workspace
+            .update_in(cx, |workspace, window, cx| {
+                let editor = cx.new(|cx| {
+                    let mut editor =
+                        Editor::for_buffer(buffer.clone(), Some(project.clone()), window, cx);
+
+                    editor.change_selections(Default::default(), window, cx, |selections| {
+                        selections.select_ranges([8..15]);
+                    });
+
+                    editor
+                });
+                workspace.add_item_to_active_pane(Box::new(editor), None, false, window, cx);
+            })
+            .unwrap();
+
+        thread_view.update_in(cx, |thread_view, window, cx| {
+            assert_eq!(thread_view.editing_message, Some(0));
+            thread_view.insert_selections(window, cx);
+        });
+
+        user_message_editor.read_with(cx, |editor, cx| {
+            let text = editor.editor().read(cx).text(cx);
+            let expected_text = String::from("Original message to edit with selection ");
+
+            assert_eq!(text, expected_text);
+        });
+    }
+
+    #[gpui::test]
+    async fn test_insert_selections(cx: &mut TestAppContext) {
+        init_test(cx);
+
+        let connection = StubAgentConnection::new();
+        connection.set_next_prompt_updates(vec![acp::SessionUpdate::AgentMessageChunk {
+            content: acp::ContentBlock::Text(acp::TextContent {
+                text: "Response".into(),
+                annotations: None,
+                meta: None,
+            }),
+        }]);
+
+        let (thread_view, cx) = setup_thread_view(StubAgentServer::new(connection), cx).await;
+        add_to_workspace(thread_view.clone(), cx);
+
+        let message_editor = cx.read(|cx| thread_view.read(cx).message_editor.clone());
+        message_editor.update_in(cx, |editor, window, cx| {
+            editor.set_text("Can you review this snippet ", window, cx)
+        });
+
+        // Create a simple buffer with some text so we can create a selection
+        // that will then be added to the message being edited.
+        let (workspace, project) = thread_view.read_with(cx, |thread_view, _cx| {
+            (thread_view.workspace.clone(), thread_view.project.clone())
+        });
+        let buffer = project.update(cx, |project, cx| {
+            project.create_local_buffer("let a = 10 + 10;", None, false, cx)
+        });
+
+        workspace
+            .update_in(cx, |workspace, window, cx| {
+                let editor = cx.new(|cx| {
+                    let mut editor =
+                        Editor::for_buffer(buffer.clone(), Some(project.clone()), window, cx);
+
+                    editor.change_selections(Default::default(), window, cx, |selections| {
+                        selections.select_ranges([8..15]);
+                    });
+
+                    editor
+                });
+                workspace.add_item_to_active_pane(Box::new(editor), None, false, window, cx);
+            })
+            .unwrap();
+
+        thread_view.update_in(cx, |thread_view, window, cx| {
+            assert_eq!(thread_view.editing_message, None);
+            thread_view.insert_selections(window, cx);
+        });
+
+        thread_view.read_with(cx, |thread_view, cx| {
+            let text = thread_view.message_editor.read(cx).text(cx);
+            let expected_txt = String::from("Can you review this snippet selection ");
+
+            assert_eq!(text, expected_txt);
+        })
+    }
 }