diff --git a/CMakeLists.txt b/CMakeLists.txt
index dfbc6796b7..a8692aebbb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -575,12 +575,6 @@ if (KWIN_BUILD_TABBOX)
     )
 endif()
 
-if (KWIN_BUILD_ACTIVITIES)
-    set(kwin_SRCS ${kwin_SRCS}
-        activities.cpp
-    )
-endif()
-
 if (HAVE_LINUX_VT_H)
     set(kwin_SRCS ${kwin_SRCS}
         virtual_terminal.cpp
@@ -681,10 +675,6 @@ set(kwin_WAYLAND_LIBS
     ${CMAKE_THREAD_LIBS_INIT}
 )
 
-if (KWIN_BUILD_ACTIVITIES)
-    set(kwin_KDE_LIBS ${kwin_KDE_LIBS} KF5::Activities)
-endif()
-
 set(kwinLibs
     ${kwin_OWN_LIBS}
     ${kwin_QT_LIBS}
@@ -716,6 +706,11 @@ if (KWIN_BUILD_CMS)
     target_link_libraries(kwin lcms2::lcms2)
 endif()
 
+if (KWIN_BUILD_ACTIVITIES)
+    target_sources(kwin PRIVATE activities.cpp)
+    target_link_libraries(kwin KF5::Activities)
+endif()
+
 generate_export_header(kwin EXPORT_FILE_NAME kwin_export.h)
 
 if(CMAKE_SYSTEM MATCHES "FreeBSD")