From c21e48450c44fbf9b08d4ed2647d7921899f47dd Mon Sep 17 00:00:00 2001
From: Kiss Lorand <50251547+kisslorand@users.noreply.github.com>
Date: Sat, 12 Sep 2026 22:21:14 +0300
Subject: [PATCH] Fix single-instance activation maximizing OrcaSlicer (#15665)

---
 src/slic3r/GUI/InstanceCheck.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/slic3r/GUI/InstanceCheck.cpp b/src/slic3r/GUI/InstanceCheck.cpp
index bc68a3f788..28c5176cb1 100644
--- a/src/slic3r/GUI/InstanceCheck.cpp
+++ b/src/slic3r/GUI/InstanceCheck.cpp
@@ -114,7 +114,10 @@ namespace instance_check_internal
 		if (my_instance_hash == other_instance_hash) {
 			BOOST_LOG_TRIVIAL(debug) << "win enum - found correct instance";
 			orca_slicer_hwnd = hwnd;
-			ShowWindow(hwnd, SW_SHOWMAXIMIZED);
+			// Do not alter the window state when opening a file in the existing instance.
+			// A minimized window still needs restoring before it can receive focus.
+			if (IsIconic(hwnd))
+				ShowWindow(hwnd, SW_RESTORE);
 			SetForegroundWindow(hwnd);
 			return false;
 		}