dim the game behind dialogs and escape menu

src/ui/CMakeLists.txt

@@ -3,6 +3,7 @@ SET(HDRS
     ${CMAKE_CURRENT_SOURCE_DIR}/VisualsConfig.h
     ${CMAKE_CURRENT_SOURCE_DIR}/VisualsLoader.h
     ${CMAKE_CURRENT_SOURCE_DIR}/MainWindow.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/ModalDimOverlay.h
     ${CMAKE_CURRENT_SOURCE_DIR}/GameWorldView.h
     ${CMAKE_CURRENT_SOURCE_DIR}/HeaderBar.h
     ${CMAKE_CURRENT_SOURCE_DIR}/BuildButtonGrid.h
@@ -21,6 +22,7 @@ SET(SRCS
     ${SRCS}
     ${CMAKE_CURRENT_SOURCE_DIR}/VisualsLoader.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/MainWindow.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/ModalDimOverlay.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/GameWorldView.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/HeaderBar.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/BuildButtonGrid.cpp