Mouse handling is way better but still want to refine it more if I can.

src/gui/event_router.hpp

@@ -8,11 +8,11 @@
 namespace gui {
   namespace routing {
     enum class State {
-      START,
-      IDLE,
-      MOUSE_ACTIVE,
-      MOUSE_MOVING,
-      MOUSE_DRAGGING
+      START=__LINE__,
+      IDLE=__LINE__,
+      MOUSE_ACTIVE=__LINE__,
+      MOUSE_MOVING=__LINE__,
+      MOUSE_DRAGGING=__LINE__
     };
 
     enum class Event {