diff --git a/src/KGantt/CMakeLists.txt b/src/KGantt/CMakeLists.txt
index 257c70e..b905f96 100644
--- a/src/KGantt/CMakeLists.txt
+++ b/src/KGantt/CMakeLists.txt
@@ -1,181 +1,182 @@
 set( KGANTTLIB_VERSION "2.6.89" )
 
 ecm_setup_version(${KGANTTLIB_VERSION}
     VARIABLE_PREFIX KGANTT
     VERSION_HEADER "${CMAKE_CURRENT_BINARY_DIR}/kgantt_version.h"
     PACKAGE_VERSION_FILE "${CMAKE_CURRENT_BINARY_DIR}/KGanttConfigVersion.cmake"
 )
 
 if(BUILD_TESTING)
     if(Qt5Test_FOUND)
         add_subdirectory(test)
     endif()
 endif()
 
 # TODO: remove this, code should be built the same with and without unit tests
 # those KGantt unit tests which are enabled in the sources should be moved into own files
 if(NOT BUILD_TESTING)
     add_definitions(-DKDAB_NO_UNIT_TESTS)
 endif()
 
 set( kgantt_LIB_SRCS
     kganttglobal.cpp
     kganttview.cpp
     kganttstyleoptionganttitem.cpp
     kganttgraphicsview.cpp
     kganttabstractrowcontroller.cpp
     kgantttreeviewrowcontroller.cpp
     kganttlistviewrowcontroller.cpp
     kganttgraphicsscene.cpp
     kganttgraphicsitem.cpp
     kganttconstraint.cpp
     kganttconstraintproxy.cpp
     kganttconstraintgraphicsitem.cpp
     kganttitemdelegate.cpp
     kganttforwardingproxymodel.cpp
     kganttsummaryhandlingproxymodel.cpp
     kganttproxymodel.cpp
     kganttconstraintmodel.cpp
     kganttabstractgrid.cpp
     kganttdatetimegrid.cpp
     kganttlegend.cpp
     kganttdatetimetimeline.cpp
     unittest/test.cpp
     unittest/testregistry.cpp
 )
 
 if(CMAKE_COMPILER_IS_GNUCXX)
 # remove once c++11-only
 # avoid warning about deprecated std::auto_ptr
 set_source_files_properties(unittest/testregistry.cpp
     PROPERTIES
         COMPILE_FLAGS "-Wno-deprecated-declarations"
 )
 endif(CMAKE_COMPILER_IS_GNUCXX)
 
 ecm_create_qm_loader(kgantt_LIB_SRCS kgantt_qt)
 
 add_library( KGantt ${kgantt_LIB_SRCS} )
 
 generate_export_header( KGantt )
 
 target_include_directories(KGantt
     INTERFACE "$<INSTALL_INTERFACE:${INCLUDE_INSTALL_DIR}/KGantt>"
 )
 
 target_link_libraries( KGantt
 PUBLIC
     Qt5::Widgets
 PRIVATE
     Qt5::PrintSupport
 )
 
 set_target_properties( KGantt PROPERTIES
   VERSION     ${KGANTT_VERSION}
   SOVERSION   ${KGANTT_SOVERSION}
   EXPORT_NAME "KGantt"
 )
 
 install( TARGETS KGantt
     EXPORT KGanttTargets
     ${INSTALL_TARGETS_DEFAULT_ARGS})
 
 ecm_generate_headers(kgantt_LIB_HEADERS
     HEADER_NAMES
     KGanttGlobal
     KGanttView
     KGanttStyleOptionGanttItem
     KGanttGraphicsView
     KGanttAbstractRowController
     KGanttTreeViewRowController
     KGanttListViewRowController
     KGanttGraphicsScene
     KGanttGraphicsItem
     KGanttConstraint
     KGanttConstraintProxy
     KGanttConstraintGraphicsItem
     KGanttItemDelegate
     KGanttForwardingProxyModel
     KGanttSummaryHandlingProxyModel
     KGanttProxyModel
     KGanttConstraintModel
     KGanttAbstractGrid
     KGanttDateTimeGrid
     KGanttLegend
     KGanttDateTimeTimeLine
 
     REQUIRED_HEADERS kgantt_LIB_HEADERS
 )
 
 install(FILES
             ${CMAKE_CURRENT_BINARY_DIR}/kgantt_export.h
             ${kgantt_LIB_HEADERS}
+            kganttabstractgrid_p.h
         DESTINATION ${INCLUDE_INSTALL_DIR}/KGantt
         COMPONENT Devel)
 
 install(FILES
     ${CMAKE_CURRENT_BINARY_DIR}/kgantt_version.h
     DESTINATION ${INCLUDE_INSTALL_DIR} COMPONENT Devel)
 
 if(BUILD_QCH)
     ecm_add_qch(
         KGantt_QCH
         NAME KGantt
         VERSION ${KGANTTLIB_VERSION}
         ORG_DOMAIN org.kde
         SOURCES
             Mainpage.dox
             ${kgantt_LIB_HEADERS}
             ${kgantt_LIB_SRCS}
         LINK_QCHS
             Qt5Core_QCH
             Qt5Gui_QCH
             Qt5Widgets_QCH
         BLANK_MACROS
             KGANTT_EXPORT
             KGANTT_DEPRECATED
         TAGFILE_INSTALL_DESTINATION ${KDE_INSTALL_QTQCHDIR}
         QCH_INSTALL_DESTINATION ${KDE_INSTALL_QTQCHDIR}
         COMPONENT Devel
     )
 endif()
 
 # create a Config.cmake and a ConfigVersion.cmake file and install them
 set(CMAKECONFIG_INSTALL_DIR "${CMAKECONFIG_INSTALL_PREFIX}/KGantt")
 
 if (BUILD_QCH)
     ecm_install_qch_export(
         TARGETS KGantt_QCH
         FILE KGanttQchTargets.cmake
         DESTINATION "${CMAKECONFIG_INSTALL_DIR}"
         COMPONENT Devel
     )
     set(PACKAGE_INCLUDE_QCHTARGETS "include(\"\${CMAKE_CURRENT_LIST_DIR}/KGanttQchTargets.cmake\")")
 endif()
 
 ecm_configure_package_config_file(
     "${CMAKE_CURRENT_SOURCE_DIR}/KGanttConfig.cmake.in"
     "${CMAKE_CURRENT_BINARY_DIR}/KGanttConfig.cmake"
     INSTALL_DESTINATION ${CMAKECONFIG_INSTALL_DIR}
 )
 
 install(FILES
             "${CMAKE_CURRENT_BINARY_DIR}/KGanttConfig.cmake"
             "${CMAKE_CURRENT_BINARY_DIR}/KGanttConfigVersion.cmake"
         DESTINATION "${CMAKECONFIG_INSTALL_DIR}"
         COMPONENT Devel)
 
 install(EXPORT KGanttTargets
         DESTINATION "${CMAKECONFIG_INSTALL_DIR}"
         FILE KGanttTargets.cmake)
 
 ecm_generate_pri_file(
     BASE_NAME KGantt
     LIB_NAME KGantt
     DEPS "widgets printsupport"
     FILENAME_VAR PRI_FILENAME
     INCLUDE_INSTALL_DIR ${INCLUDE_INSTALL_DIR}/KGantt
 )
 
 install(FILES ${PRI_FILENAME}
         DESTINATION ${ECM_MKSPECS_INSTALL_DIR})