diff --git a/milou5.spec b/milou5.spec
index 79e526d..7e22d64 100644
--- a/milou5.spec
+++ b/milou5.spec
@@ -34,6 +34,7 @@ BuildRequires:  cmake(KF5I18n) >= 5.25.0
 BuildRequires:  cmake(KF5Plasma) >= 5.25.0
 BuildRequires:  cmake(KF5Runner) >= 5.25.0
 BuildRequires:  cmake(KF5Service) >= 5.25.0
+BuildRequires:  cmake(KF5WindowSystem) >= 5.25.0
 BuildRequires:  cmake(Qt5Qml) >= 5.4.0
 BuildRequires:  cmake(Qt5Quick) >= 5.4.0
 BuildRequires:  cmake(Qt5Script) >= 5.4.0