diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1f4d3ce..e6b6f88 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -30,7 +30,7 @@ else()
     set(LIBRW_PLATFORM_GL3_REQUIRES_OPENGL ON)
 endif()
 list(GET LIBRW_PLATFORMS 0 LIBRW_PLATFORM_DEFAULT)
-set(LIBRW_PLATFORM "${LIBRW_PLATFORM_DEFAULT}" CACHE STRING "Platform")
+set(LIBRW_PLATFORM "${LIBRW_PLATFORM_DEFAULT}" CACHE STRING "Platform (choices=${LIBRW_PLATFORMS})")
 set_property(CACHE LIBRW_PLATFORM PROPERTY STRINGS ${LIBRW_PLATFORMS})
 message(STATUS "LIBRW_PLATFORM = ${LIBRW_PLATFORM} (choices=${LIBRW_PLATFORMS})")
 set("LIBRW_PLATFORM_${LIBRW_PLATFORM}" ON)
@@ -39,7 +39,7 @@ if(NOT LIBRW_PLATFORM IN_LIST LIBRW_PLATFORMS)
 endif()
 
 set(LIBRW_GL3_GFXLIBS "GLFW" "SDL2")
-set(LIBRW_GL3_GFXLIB "GLFW" CACHE STRING "gfxlib for gl3")
+set(LIBRW_GL3_GFXLIB "GLFW" CACHE STRING "gfxlib for gl3 (choices=${LIBRW_GL3_GFXLIBS})")
 set_property(CACHE LIBRW_GL3_GFXLIB PROPERTY STRINGS ${LIBRW_GL3_GFXLIBS})
 if(LIBRW_PLATFORM_GL3)
     message(STATUS "LIBRW_GL3_GFXLIB = ${LIBRW_GL3_GFXLIB} (choices=${LIBRW_GL3_GFXLIBS})")