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fix(cua-driver-rs)(windows): overlay stops escaping into topmost band, foreground app renders above pin #1688

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Merged
f-trycua merged 1 commit into from
May 24, 2026
Merged

fix(cua-driver-rs)(windows): overlay stops escaping into topmost band, foreground app renders above pin #1688

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44 changes: 32 additions & 12 deletions libs/cua-driver/rust/crates/platform-windows/src/overlay.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -445,19 +445,39 @@ unsafe fn reapply_z_order(hwnd: windows::Win32::Foundation::HWND) {
guard.as_ref().and_then(|rs| rs.core.pinned_wid)
};

// If a target window is pinned, place the overlay just above it.
// Falls back to HWND_TOP when not set or when the target is gone.
let insert_after = if let Some(wid) = pinned_wid {
let target = HWND(wid as *mut _);
if IsWindow(target).as_bool() {
target
} else {
HWND_TOPMOST
}
} else {
HWND_TOPMOST
};
let pinned_target = pinned_wid.and_then(|wid| {
let h = HWND(wid as *mut _);
if IsWindow(h).as_bool() { Some(h) } else { None }
});

// The overlay must sit JUST above the pinned target window so the
// user's foreground app (a different non-topmost window — say their
// terminal) renders on top of the overlay. Two pitfalls:
//
// 1. HWND_TOPMOST was the previous fallback. Once Windows promotes
// a window into the topmost band (sets WS_EX_TOPMOST), a later
// SetWindowPos with a normal target_hwnd does NOT drop it back
// out — the overlay stays above EVERYTHING non-topmost (incl.
// the user's foreground). That was the symptom in #1688-style
// reports: overlay sticks visible over a terminal even when
// the pinned window (Calculator) is behind it.
// 2. To drop out of the topmost band, we need an explicit
// SetWindowPos(hwnd, HWND_NOTOPMOST, …) call. Then we can
// issue a second SetWindowPos with the real target_hwnd so
// the overlay lands ABOVE the pin but BELOW any window
// currently above the pin (the user's foreground).
//
// Fallback when there's no live pin: HWND_TOP — top of non-topmost
// band, NOT the topmost band. So a "no pin" overlay still respects
// the user's foreground stack.
let _ = SetWindowPos(
hwnd,
HWND_NOTOPMOST,
0, 0, 0, 0,
SWP_NOMOVE | SWP_NOSIZE | SWP_NOACTIVATE | SWP_NOOWNERZORDER,
);

let insert_after = pinned_target.unwrap_or(HWND_TOP);
let _ = SetWindowPos(
hwnd,
insert_after,
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