From 4126822be88eb23ff0c41462fed7341634717533 Mon Sep 17 00:00:00 2001
From: l0ng-ai <24760907+l0ng-ai@users.noreply.github.com>
Date: Tue, 10 Nov 2026 00:53:59 +0800
Subject: [PATCH] fix(window): preserve fullscreen when adding project tabs
 (#2389)

Adding a project to a native macOS tab group anchored the group on the newly opened window, so AppKit took that window's normal frame and the group left full screen (black margins, stacked title bar and tab strip). Tab sync now anchors on the group's currently selected window and only selects the new tab. Verified on macOS with the system tab preference set to always and manual, in full screen and windowed: open, switch, close, merge and detach tabs. Fixes #2224.
---
 src-tauri/src/macos.rs         | 17 ++++++++++++-----
 src-tauri/src/window_groups.rs |  3 ++-
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/src-tauri/src/macos.rs b/src-tauri/src/macos.rs
index af1052f8a..4053be31f 100644
--- a/src-tauri/src/macos.rs
+++ b/src-tauri/src/macos.rs
@@ -83,16 +83,23 @@ fn same_group(a: &NSWindow, b: &NSWindow) -> bool {
     }
 }
 
-/// Puts `members` in one native tab group and shows `selected`.
-pub fn sync_tab_group(members: Vec<WebviewWindow>, selected: &WebviewWindow) -> tauri::Result<()> {
+/// Adds `members` to the existing anchor's native tab group and shows `selected`.
+pub fn sync_tab_group(
+    members: Vec<WebviewWindow>,
+    anchor: &WebviewWindow,
+    selected: &WebviewWindow,
+) -> tauri::Result<()> {
+    let anchor = anchor.clone();
     let target = selected.clone();
     on_main(selected, move || {
         let Some(shown) = native(&target) else { return };
-        for member in members.iter().filter(|m| m.label() != target.label()) {
+        let Some(anchor_window) = native(&anchor) else { return };
+        // Joining into a new tab's desktop window would take the existing group out of full screen.
+        for member in members.iter().filter(|m| m.label() != anchor.label()) {
             if let Some(window) = native(member)
-                && !same_group(shown, window)
+                && !same_group(anchor_window, window)
             {
-                shown.addTabbedWindow_ordered(window, objc2_app_kit::NSWindowOrderingMode::Above);
+                anchor_window.addTabbedWindow_ordered(window, objc2_app_kit::NSWindowOrderingMode::Above);
             }
         }
         if let Some(group) = shown.tabGroup() {
diff --git a/src-tauri/src/window_groups.rs b/src-tauri/src/window_groups.rs
index 699a7a00c..85335be40 100644
--- a/src-tauri/src/window_groups.rs
+++ b/src-tauri/src/window_groups.rs
@@ -100,8 +100,9 @@ pub fn select(app: &AppHandle, caller: &str, target: &str) -> IdeResult<()> {
 #[cfg(target_os = "macos")]
 fn native_select(app: &AppHandle, group: &Group, to: &WebviewWindow) -> IdeResult<()> {
     let members = group.members.iter().filter_map(|m| app.get_webview_window(m)).collect();
+    let anchor = app.get_webview_window(&group.selected).unwrap_or_else(|| to.clone());
     to.unminimize().map_err(|e| IdeError::internal(e.to_string()))?;
-    crate::macos::sync_tab_group(members, to).map_err(|e| IdeError::internal(e.to_string()))
+    crate::macos::sync_tab_group(members, &anchor, to).map_err(|e| IdeError::internal(e.to_string()))
 }
 
 #[cfg(target_os = "macos")]