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Make Focus() / Blur() reliable and let Blur() return focus to the previous app #69
Description
Window::Focus() and Blur() follow the platforms' simplest calls and fail in common cases:
- Windows:
Focus()isSetForegroundWindow+SetFocus, which the foreground lock refuses when the app isn't in the foreground (only the taskbar flashes). Consider theAttachThreadInput/AllowSetForegroundWindowapproaches, and checkIsFocused()after focus changes. - Linux:
gtk_window_present()without a timestamp is subject to focus-stealing prevention; usegtk_window_present_with_time()with the last event time. Blur()should hand focus back to the previously active window or app. On macOS it only doesorderBack:, and on WindowsSetFocus(nullptr), which leaves the app active. Typical use: a launcher/search bar that hides and pastes into the previous app. Related: libnativeapi/nativeapi#59 (app-level hide on macOS).
Background:
- setFocus not always work and isFocused is always false. leanflutter/window_manager#364: focus() not always working, isFocused() always false (Windows)
- [Linux] WindowManager.focus() does not focus the window. Ubuntu. leanflutter/window_manager#218: focus() doesn't focus the window on Ubuntu
- How to unfocus window? leanflutter/window_manager#387: how to unfocus the window and bring back the previous one
- Is there any way to focus on the previous window when I call windowManager.hide()? leanflutter/window_manager#352: focus the previous window when hiding
Activity
Make Focus() reliable and let Blur() return focus to where it was
lijy91 commentedon Oct 6, 2026
Implemented in 8553d4d (workspace: libnativeapi/nativeapi@02c2e5a). No signature changes; the platform behavior is documented on
Focus()/Blur().Focus()andShow()remember the window or app that had the focus.Blur()hands it back, falls back to the window the platform would pick next, and does nothing on a window without focus.Blur()keys the previous own window, or yields activation to the previous app and activates it.AttachThreadInputwhen the foreground lock refuses; doesn't steal a child HWND's focus (Flutter).Blur()gives the foreground to the recorded window, else the next one down the Z order.Blur()presents the previous own window, or on X11 activates the previous client's window (else the next in_NET_CLIENT_LIST_STACKING) through_NET_ACTIVE_WINDOWas a pager. Wayland can only return focus to another window of the same app.Verified (no mouse or keyboard input; the anchor is a second process):
Tests:
tests/window_focus_return_test.cpp(Windows, Linux X11),tests/window_focus_return_macos_test.mm.Still open: a real GNOME/KDE desktop run. Keeping this open until then.
lijy91 commentedon Oct 7, 2026
GNOME result (Ubuntu 24.04, GNOME 46, core 1097ca6):
tests/window_focus_return_testpasses completely under GNOME's Xwayland with Mutter as the window manager:Focus()from a background process,Blur()back to the previous own window and to another process's window, and the fallback to the next window in_NET_CLIENT_LIST_STACKING.Still not covered: native Wayland clients (Wayland only allows returning focus to the same app's windows, as documented) and KDE.