diff --git i/CMakeLists.txt w/CMakeLists.txt
index 986094be..9e871543 100644
--- i/CMakeLists.txt
+++ w/CMakeLists.txt
@@ -277,7 +277,7 @@ if(BUILD_VIEWER)
   set(FLTK_SKIP_FLUID TRUE)
   set(FLTK_SKIP_OPENGL TRUE)
   set(FLTK_SKIP_FORMS TRUE)
-  find_package(FLTK REQUIRED)
+  find_package(FLTK1.3 REQUIRED)
 
   if(UNIX AND NOT APPLE)
     # No proper handling for extra X11 libs that FLTK might need...
@@ -305,11 +305,6 @@ if(BUILD_VIEWER)
   set(CMAKE_REQUIRED_INCLUDES ${FLTK_INCLUDE_DIR})
   set(CMAKE_REQUIRED_LIBRARIES ${FLTK_LIBRARIES})
 
-  check_cxx_source_compiles("#include <FL/Fl.H>\n#if FL_MAJOR_VERSION != 1 || FL_MINOR_VERSION != 3\n#error Wrong FLTK version\n#endif\nint main(int, char**) { return 0; }" OK_FLTK_VERSION)
-  if(NOT OK_FLTK_VERSION)
-    message(FATAL_ERROR "Incompatible version of FLTK")
-  endif()
-
   set(CMAKE_REQUIRED_FLAGS)
   set(CMAKE_REQUIRED_INCLUDES)
   set(CMAKE_REQUIRED_LIBRARIES)