diff --git a/ConfigureChecks.cmake b/ConfigureChecks.cmake
index 6f9ca9f6..ad02711e 100644
--- a/ConfigureChecks.cmake
+++ b/ConfigureChecks.cmake
@@ -155,7 +155,7 @@ tde_restore( CMAKE_REQUIRED_INCLUDES CMAKE_REQUIRED_LIBRARIES )
 if( WITH_KONQSIDEBAR )
   tde_save( CMAKE_REQUIRED_DEFINITIONS CMAKE_REQUIRED_INCLUDES CMAKE_REQUIRED_LIBRARIES CMAKE_REQUIRED_LIBRARIES )
   set( CMAKE_REQUIRED_DEFINITIONS ${TQT_CFLAGS_OTHER} )
-  set( CMAKE_REQUIRED_INCLUDES ${TDE_INCLUDE_DIR};${TQT_INCLUDE_DIRS} )
+  set( CMAKE_REQUIRED_INCLUDES ${TDE_INCLUDE_DIR};${TQT_INCLUDE_DIRS};${CMAKE_INCLUDE_PATH} )
   set( CMAKE_REQUIRED_FLAGS "-include tqt.h" )
   set( CMAKE_REQUIRED_LIBRARIES -L${QT_LIBRARY_DIRS} ${QT_LIBRARIES} )
   check_cxx_source_compiles("