diff --git a/src/dlangui/core/config.d b/src/dlangui/core/config.d
index 81329cfc..60d935db 100644
--- a/src/dlangui/core/config.d
+++ b/src/dlangui/core/config.d
@@ -1,12 +1,12 @@
 module dlangui.core.config;
 
 version (USE_FREETYPE) {
-    immutable bool USE_FREETYPE = true;
+    enum USE_FREETYPE = true;
 } else {
     version (Windows) {
-        immutable bool ENABLE_FREETYPE = false;
+        enum ENABLE_FREETYPE = false;
     } else {
-        immutable bool ENABLE_FREETYPE = true;
+        enum ENABLE_FREETYPE = true;
     }
 }
 
@@ -14,76 +14,76 @@ version (USE_FREETYPE) {
 version (USE_SDL) {
     // SDL backend already selected using version identifier
     version (USE_OPENGL) {
-        immutable bool ENABLE_OPENGL = true;
+        enum ENABLE_OPENGL = true;
     } else {
-        immutable bool ENABLE_OPENGL = false;
+        enum ENABLE_OPENGL = false;
     }
-    immutable bool BACKEND_SDL = true;
-    immutable bool BACKEND_X11 = false;
-    immutable bool BACKEND_DSFML = false;
-    immutable bool BACKEND_WIN32 = false;
+    enum BACKEND_SDL = true;
+    enum BACKEND_X11 = false;
+    enum BACKEND_DSFML = false;
+    enum BACKEND_WIN32 = false;
 } else version (USE_X11) {
     // X11 backend already selected using version identifier
     version (USE_OPENGL) {
-        immutable bool ENABLE_OPENGL = true;
+        enum ENABLE_OPENGL = true;
     } else {
-        immutable bool ENABLE_OPENGL = false;
+        enum ENABLE_OPENGL = false;
     }
-    immutable bool BACKEND_SDL = false;
-    immutable bool BACKEND_X11 = true;
-    immutable bool BACKEND_DSFML = false;
-    immutable bool BACKEND_WIN32 = false;
+    enum BACKEND_SDL = false;
+    enum BACKEND_X11 = true;
+    enum BACKEND_DSFML = false;
+    enum BACKEND_WIN32 = false;
 } else version (USE_WIN32) {
     // Win32 backend already selected using version identifier
     version (USE_OPENGL) {
-        immutable bool ENABLE_OPENGL = true;
+        enum ENABLE_OPENGL = true;
     } else {
-        immutable bool ENABLE_OPENGL = false;
+        enum ENABLE_OPENGL = false;
     }
-    immutable bool BACKEND_SDL = false;
-    immutable bool BACKEND_X11 = false;
-    immutable bool BACKEND_DSFML = false;
-    immutable bool BACKEND_WIN32 = true;
+    enum BACKEND_SDL = false;
+    enum BACKEND_X11 = false;
+    enum BACKEND_DSFML = false;
+    enum BACKEND_WIN32 = true;
 } else version (USE_DSFML) {
     // DSFML backend already selected using version identifier
     version (USE_OPENGL) {
-        immutable bool ENABLE_OPENGL = true;
+        enum ENABLE_OPENGL = true;
     } else {
-        immutable bool ENABLE_OPENGL = false;
+        enum ENABLE_OPENGL = false;
     }
-    immutable bool BACKEND_SDL = false;
-    immutable bool BACKEND_X11 = false;
-    immutable bool BACKEND_DSFML = true;
-    immutable bool BACKEND_WIN32 = false;
+    enum BACKEND_SDL = false;
+    enum BACKEND_X11 = false;
+    enum BACKEND_DSFML = true;
+    enum BACKEND_WIN32 = false;
 } else {
     // no backend selected: set default based on platform
     version (Windows) {
         // For Windows
-        immutable bool ENABLE_OPENGL = true;
-        immutable bool BACKEND_SDL = false;
-        immutable bool BACKEND_X11 = false;
-        immutable bool BACKEND_DSFML = false;
-        immutable bool BACKEND_WIN32 = true;
+        enum ENABLE_OPENGL = true;
+        enum BACKEND_SDL = false;
+        enum BACKEND_X11 = false;
+        enum BACKEND_DSFML = false;
+        enum BACKEND_WIN32 = true;
     } else version(linux) {
         // Default for Linux: use SDL and OpenGL
-        immutable bool ENABLE_OPENGL = true;
-        immutable bool BACKEND_SDL = true;
-        immutable bool BACKEND_X11 = false;
-        immutable bool BACKEND_DSFML = false;
-        immutable bool BACKEND_WIN32 = false;
+        enum ENABLE_OPENGL = true;
+        enum BACKEND_SDL = true;
+        enum BACKEND_X11 = false;
+        enum BACKEND_DSFML = false;
+        enum BACKEND_WIN32 = false;
     } else version(OSX) {
         // Default: use SDL and OpenGL
-        immutable bool ENABLE_OPENGL = true;
-        immutable bool BACKEND_SDL = true;
-        immutable bool BACKEND_X11 = false;
-        immutable bool BACKEND_DSFML = false;
-        immutable bool BACKEND_WIN32 = false;
+        enum ENABLE_OPENGL = true;
+        enum BACKEND_SDL = true;
+        enum BACKEND_X11 = false;
+        enum BACKEND_DSFML = false;
+        enum BACKEND_WIN32 = false;
     } else {
         // Unknown platform: use SDL and OpenGL
-        immutable bool ENABLE_OPENGL = true;
-        immutable bool BACKEND_SDL = true;
-        immutable bool BACKEND_X11 = false;
-        immutable bool BACKEND_DSFML = false;
-        immutable bool BACKEND_WIN32 = false;
+        enum ENABLE_OPENGL = true;
+        enum BACKEND_SDL = true;
+        enum BACKEND_X11 = false;
+        enum BACKEND_DSFML = false;
+        enum BACKEND_WIN32 = false;
     }
 }