diff --git a/examples/directx11_example/main.cpp b/examples/directx11_example/main.cpp
index ea9a341..84d8673 100644
--- a/examples/directx11_example/main.cpp
+++ b/examples/directx11_example/main.cpp
@@ -317,7 +317,7 @@
         io.MouseDown[1] = false; 
         return true;
     case WM_MOUSEWHEEL:
-        io.MouseWheel = GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1.0f : -1.0f;
+        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.)

diff --git a/examples/directx11_example/main.cpp b/examples/directx11_example/main.cpp
index ea9a341..84d8673 100644
--- a/examples/directx11_example/main.cpp
+++ b/examples/directx11_example/main.cpp
@@ -317,7 +317,7 @@
         io.MouseDown[1] = false; 
         return true;
     case WM_MOUSEWHEEL:
-        io.MouseWheel = GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1.0f : -1.0f;
+        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.)
diff --git a/examples/directx9_example/main.cpp b/examples/directx9_example/main.cpp
index adb2bf3..047874c 100644
--- a/examples/directx9_example/main.cpp
+++ b/examples/directx9_example/main.cpp
@@ -153,7 +153,7 @@
         io.MouseDown[1] = false; 
         return true;
     case WM_MOUSEWHEEL:
-        io.MouseWheel = GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1.0f : -1.0f;
+        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.)

diff --git a/examples/directx11_example/main.cpp b/examples/directx11_example/main.cpp
index ea9a341..84d8673 100644
--- a/examples/directx11_example/main.cpp
+++ b/examples/directx11_example/main.cpp
@@ -317,7 +317,7 @@
         io.MouseDown[1] = false; 
         return true;
     case WM_MOUSEWHEEL:
-        io.MouseWheel = GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1.0f : -1.0f;
+        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.)
diff --git a/examples/directx9_example/main.cpp b/examples/directx9_example/main.cpp
index adb2bf3..047874c 100644
--- a/examples/directx9_example/main.cpp
+++ b/examples/directx9_example/main.cpp
@@ -153,7 +153,7 @@
         io.MouseDown[1] = false; 
         return true;
     case WM_MOUSEWHEEL:
-        io.MouseWheel = GET_WHEEL_DELTA_WPARAM(wParam) > 0 ? +1.0f : -1.0f;
+        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.)
diff --git a/examples/opengl_example/main.cpp b/examples/opengl_example/main.cpp
index 22e2b1b..61a9f36 100644
--- a/examples/opengl_example/main.cpp
+++ b/examples/opengl_example/main.cpp
@@ -114,7 +114,7 @@
 static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
 {
     ImGuiIO& io = ImGui::GetIO();
-    io.MouseWheel = (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 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)
@@ -258,7 +258,6 @@
     {
         ImGuiIO& io = ImGui::GetIO();
         mousePressed[0] = mousePressed[1] = false;
-        io.MouseWheel = 0;
         glfwPollEvents();
         UpdateImGui();