Example code: warning fix + comments.

examples/directx9_example/main.cpp

@@ -154,8 +154,8 @@ LRESULT WINAPI MsgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
         io.MouseDown[1] = false; 
         return true;
     case WM_MOUSEWHEEL:
-        // Mouse wheel: -1,0,+1
-        io.MouseWheel = GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1 : -1;
+        // Mouse wheel uses integer on Windows
+        io.MouseWheel = GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1.0f : -1.0f;
         return true;
     case WM_MOUSEMOVE:
         // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)

examples/opengl_example/main.cpp

@@ -131,7 +131,7 @@ static void glfw_mouse_button_callback(GLFWwindow* window, int button, int actio
 static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
 {
     ImGuiIO& io = ImGui::GetIO();
-    io.MouseWheel = yoffset; // Use fractional mouse wheel, 1.0 unit 3 lines.
+    io.MouseWheel = (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines.
 }
 
 static void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)

imgui.h

@@ -488,7 +488,7 @@ struct ImGuiIO
 
     ImVec2      MousePos;                   // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
     bool        MouseDown[5];               // Mouse buttons. ImGui itself only uses button 0 (left button) but you can use others as storage for convenience.
-    float       MouseWheel;                 // Mouse wheel: 1 unit scrolls about 3 lines text.  
+    float       MouseWheel;                 // Mouse wheel: 1 unit scrolls about 5 lines text.  
     bool        KeyCtrl;                    // Keyboard modifier pressed: Control
     bool        KeyShift;                   // Keyboard modifier pressed: Shift
     bool        KeysDown[512];              // Keyboard keys that are pressed (in whatever order user naturally has access to keyboard data)