feat(dnd): tear-off window matches pane size and grab position

agentmux-cef/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "agentmux-cef"
-version = "0.33.56"
+version = "0.33.58"
 description = "AgentMux CEF Host — Pinned Chromium renderer replacing system WebView2"
 authors = ["AgentMux Corp"]
 edition = "2021"

agentmux-cef/src/commands/drag.rs

@@ -275,15 +275,23 @@ pub fn open_window_at_position(state: &Arc<AppState>, args: &serde_json::Value)
     let window_id = uuid::Uuid::new_v4();
     let label = format!("window-{}", window_id.simple());
 
-    let win_w = 1200i32;
-    let win_h = 800i32;
+    // Use pane dimensions from the frontend if provided; fall back to defaults.
+    let win_w = args.get("width").and_then(|v| v.as_f64()).map(|v| (v as i32).max(400)).unwrap_or(1200);
+    let win_h = args.get("height").and_then(|v| v.as_f64()).map(|v| (v as i32).max(300)).unwrap_or(800);
 
-    // Position so cursor lands near top-center of title bar
-    let pos_x = ((screen_x - win_w as f64 / 2.0).max(0.0)) as i32;
-    let pos_y = ((screen_y - 16.0).max(0.0)) as i32;
+    // Cursor grab offset within the pane (where the user grabbed it).
+    // Positions the new window so the cursor lands at the same relative point.
+    // Falls back to top-center / title-bar-offset if not provided.
+    let grab_dx = args.get("grabOffsetX").and_then(|v| v.as_f64()).map(|v| v as i32).unwrap_or(win_w / 2);
+    let grab_dy = args.get("grabOffsetY").and_then(|v| v.as_f64()).map(|v| v as i32).unwrap_or(20);
+
+    let pos_x = ((screen_x as i32) - grab_dx).max(0);
+    let pos_y = ((screen_y as i32) - grab_dy).max(0);
 
     tracing::info!(
         label = %label, pos_x = %pos_x, pos_y = %pos_y,
+        win_w = %win_w, win_h = %win_h,
+        grab_dx = %grab_dx, grab_dy = %grab_dy,
         workspace_id = %workspace_id,
         "[dnd:cef] open_window_at_position"
     );

agentmux-cef/src/commands/mod.rs

@@ -11,6 +11,7 @@ pub mod providers;
 pub mod drag;
 pub mod clipboard;
 pub mod stubs;
+pub mod palette;
 
 use std::sync::Arc;
 use crate::state::AppState;

agentmux-cef/src/commands/palette.rs

@@ -0,0 +1,50 @@
+// Copyright 2026, AgentMux Corp.
+// SPDX-License-Identifier: Apache-2.0
+//
+// `run_command` IPC handler — dispatches a command ID to the frontend registry.
+//
+// The Rust side does not own the command registry; it simply forwards the ID
+// to the frontend via a CEF `CustomEvent`. The frontend's `commandRegistry.run(id)`
+// handles validation and execution.
+
+use std::sync::Arc;
+
+use cef::{CefString, ImplBrowser, ImplFrame};
+
+use crate::state::AppState;
+
+/// Dispatch a command palette ID to the frontend of the target window.
+///
+/// Args:
+///   `id`          — stable command ID (e.g. `"open:terminal"`)
+///   `windowLabel` — (optional) which window to target; defaults to `"main"`
+pub fn run_command(state: &Arc<AppState>, args: &serde_json::Value) -> Result<serde_json::Value, String> {
+    let id = args["id"]
+        .as_str()
+        .ok_or_else(|| "run_command: missing 'id' field".to_string())?;
+
+    let window_label = args["windowLabel"].as_str().unwrap_or("main");
+
+    let js = format!(
+        "window.dispatchEvent(new CustomEvent('agentmux-run-command', {{ detail: {{ id: {:?} }} }}));",
+        id
+    );
+
+    let browsers = state.browsers.lock();
+    let browser = browsers
+        .get(window_label)
+        .or_else(|| browsers.values().next());
+
+    if let Some(browser) = browser {
+        if let Some(frame) = browser.main_frame() {
+            let code = CefString::from(js.as_str());
+            let url = CefString::from("");
+            frame.execute_java_script(Some(&code), Some(&url), 0);
+            tracing::debug!(id = %id, window = %window_label, "[palette] dispatched run_command");
+        }
+    } else {
+        tracing::warn!(id = %id, "[palette] run_command: no browser available");
+    }
+
+    Ok(serde_json::Value::Null)
+}

agentmux-cef/src/ipc.rs

@@ -270,6 +270,9 @@ async fn route_command(
         "open_in_editor" => commands::platform::open_in_editor(args),
         "copy_file_to_dir" => commands::providers::copy_file_to_dir(args),
 
+        // ---- Command palette ----
+        "run_command" => commands::palette::run_command(state, args),
+
         // ---- Unknown command ----
         _ => Err(format!("Unknown command: {}", cmd)),
     }

agentmux-launcher/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "agentmux-launcher"
-version = "0.33.56"
+version = "0.33.58"
 description = "AgentMux Launcher — tiny exe that sets DLL path then spawns the CEF host"
 authors = ["AgentMux Corp"]
 edition = "2021"

agentmux-srv/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "agentmux-srv"
-version = "0.33.56"
+version = "0.33.58"
 edition = "2021"
 description = "AgentMux Rust backend server"
 

agentmux-wsh/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "agentmux-wsh"
-version = "0.33.56"
+version = "0.33.58"
 edition = "2021"
 description = "Shell integration CLI for AgentMux"
 

frontend/app/drag/CrossWindowDragMonitor.platform.tsx

@@ -5,4 +5,4 @@
 // at build time by Vite's platformResolve plugin.
 // Do NOT import this file directly in application code.
 export { CrossWindowDragMonitor, setCurrentDragPayload, getCurrentDragPayload } from "./CrossWindowDragMonitor.win32";
-export type { DragItemPayload } from "./CrossWindowDragMonitor.win32";
+export type { DragItemPayload, GrabOffset, PaneRect } from "./CrossWindowDragMonitor.win32";

frontend/app/drag/CrossWindowDragMonitor.tsx

@@ -5,4 +5,4 @@
 // Import from this file directly (e.g. `import { setCurrentDragPayload } from "@/app/drag/CrossWindowDragMonitor"`)
 // and Vite's platformResolve plugin will pick the right .win32/.darwin/.linux variant.
 export { CrossWindowDragMonitor, setCurrentDragPayload, getCurrentDragPayload } from "./CrossWindowDragMonitor.platform";
-export type { DragItemPayload } from "./CrossWindowDragMonitor.platform";
+export type { DragItemPayload, GrabOffset, PaneRect } from "./CrossWindowDragMonitor.platform";

frontend/app/drag/CrossWindowDragMonitor.win32.tsx

@@ -30,8 +30,11 @@ import type { JSX } from "solid-js";
 import type { LayoutNode } from "@/layout/lib/types";
 
 // Shared drag state set by TileLayout / TabBar drag handlers
+export type PaneRect = { x: number; y: number; w: number; h: number };
+export type GrabOffset = { dx: number; dy: number };
+
 export type DragItemPayload =
-    | { kind: "tile"; node: LayoutNode }
+    | { kind: "tile"; node: LayoutNode; paneRect?: PaneRect; grabOffset?: GrabOffset }
     | { kind: "tab"; tabId: string; workspaceId: string; isPinned: boolean };
 
 // Module-level drag state so TileLayout/TabBar can set it before dragend fires
@@ -190,7 +193,7 @@ async function handleCrossWindowDragEnd(payload: DragItemPayload, sourceWindow:
             await performCrossWindowDrop(dragType, dragPayloadForApi, workspace.oid, activeTabId);
             await api.completeCrossDrag(dragId, targetWindow, cursorPoint.x, cursorPoint.y);
         } else if (!targetWindow) {
-            await performTearOff(dragType, dragPayloadForApi, workspace.oid, activeTabId, cursorPoint.x, cursorPoint.y);
+            await performTearOff(dragType, dragPayloadForApi, workspace.oid, activeTabId, cursorPoint.x, cursorPoint.y, payload);
             await api.completeCrossDrag(dragId, null, cursorPoint.x, cursorPoint.y);
             try { await api.releaseDragCapture(); } catch {}
         } else {
@@ -216,9 +219,13 @@ async function performTearOff(
     sourceWsId: string,
     sourceTabId: string,
     screenX: number,
-    screenY: number
+    screenY: number,
+    dragPayload: DragItemPayload | null
 ) {
     const api = getApi();
+    const paneRect   = dragPayload?.kind === "tile" ? dragPayload.paneRect   : undefined;
+    const grabOffset = dragPayload?.kind === "tile" ? dragPayload.grabOffset : undefined;
+
     if (dragType === "pane" && payload.blockId) {
         const newWsId = await WorkspaceService.TearOffBlock(payload.blockId, sourceTabId, sourceWsId, true);
         if (newWsId) {
@@ -234,7 +241,11 @@ async function performTearOff(
                     } as LayoutTreeDeleteNodeAction);
                 }
             }
-            await api.openWindowAtPosition(screenX, screenY, newWsId);
+            await api.openWindowAtPosition(
+                screenX, screenY, newWsId,
+                paneRect?.w, paneRect?.h,
+                grabOffset?.dx, grabOffset?.dy
+            );
         }
     } else if (dragType === "tab" && payload.tabId) {
         const newWsId = await WorkspaceService.TearOffTab(payload.tabId, sourceWsId);

frontend/app/modals/command-palette.scss

@@ -0,0 +1,137 @@
+// Copyright 2026, AgentMux Corp.
+// SPDX-License-Identifier: Apache-2.0
+
+.command-palette-backdrop {
+    position: fixed;
+    inset: 0;
+    background: rgba(0, 0, 0, 0.45);
+    z-index: 900;
+}
+
+.command-palette-container {
+    position: fixed;
+    top: 20%;
+    left: 50%;
+    transform: translateX(-50%);
+    width: 560px;
+    max-height: 480px;
+    background: var(--modal-bg-color, #1e1e1e);
+    border: 1px solid var(--border-color, #444);
+    border-radius: 8px;
+    box-shadow: 0 16px 48px rgba(0, 0, 0, 0.6);
+    z-index: 901;
+    display: flex;
+    flex-direction: column;
+    overflow: hidden;
+
+    // Ensure command palette is above all other content
+    isolation: isolate;
+}
+
+.command-palette-input-row {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    padding: 10px 14px;
+    border-bottom: 1px solid var(--border-color, #444);
+    flex-shrink: 0;
+}
+
+.command-palette-search-icon {
+    color: var(--secondary-text-color, #888);
+    font-size: 13px;
+    flex-shrink: 0;
+}
+
+.command-palette-input {
+    flex: 1;
+    background: transparent;
+    border: none;
+    outline: none;
+    color: var(--main-text-color, #e0e0e0);
+    font-size: 14px;
+    font-family: var(--base-font, inherit);
+    line-height: 1.5;
+
+    &::placeholder {
+        color: var(--secondary-text-color, #666);
+    }
+}
+
+.command-palette-esc-hint {
+    font-size: 10px;
+    color: var(--secondary-text-color, #666);
+    background: var(--panel-bg-color, #2a2a2a);
+    border: 1px solid var(--border-color, #444);
+    border-radius: 3px;
+    padding: 1px 5px;
+    flex-shrink: 0;
+    font-family: var(--base-font, inherit);
+}
+
+.command-palette-list {
+    overflow-y: auto;
+    flex: 1;
+    padding: 4px 0;
+
+    &::-webkit-scrollbar {
+        width: 6px;
+    }
+    &::-webkit-scrollbar-track {
+        background: transparent;
+    }
+    &::-webkit-scrollbar-thumb {
+        background: var(--border-color, #555);
+        border-radius: 3px;
+    }
+}
+
+.command-palette-item {
+    display: flex;
+    align-items: center;
+    gap: 10px;
+    padding: 7px 14px;
+    cursor: pointer;
+    user-select: none;
+
+    &.selected {
+        background: var(--highlight-bg-color, #2d4a6e);
+    }
+
+    &:hover:not(.selected) {
+        background: var(--hover-bg-color, #2a2a2a);
+    }
+}
+
+.command-palette-item-icon {
+    font-size: 13px;
+    color: var(--secondary-text-color, #888);
+    width: 16px;
+    text-align: center;
+    flex-shrink: 0;
+}
+
+.command-palette-item-label {
+    flex: 1;
+    font-size: 13px;
+    color: var(--main-text-color, #e0e0e0);
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+}
+
+.command-palette-item-category {
+    font-size: 11px;
+    color: var(--secondary-text-color, #666);
+    flex-shrink: 0;
+    text-transform: uppercase;
+    letter-spacing: 0.04em;
+}
+
+.command-palette-empty {
+    padding: 24px 14px;
+    text-align: center;
+    color: var(--secondary-text-color, #666);
+    font-size: 13px;
+    font-style: italic;
+}