diff --git a/CMakeLists.txt b/CMakeLists.txt
index 11927c11..61c86aed 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -174,6 +174,8 @@ if (ISLE_BUILD_LIB)
     LEGO1/skateboard.cpp
     LEGO1/towtrack.cpp
     LEGO1/towtrackmissionstate.cpp
+    LEGO1/mxstringvariable.cpp
+    LEGO1/legobackbackground.cpp
   )
 
   # Link libraries