diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 76703d745..b30685f5a 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -49,7 +49,7 @@ Other Changes:
   clipping, more than 16 KB characters are visible in the same low-level ImDrawList::RenderText
   call. ImGui-level functions such as TextUnformatted() are not affected. This is quite rare
   but it will be addressed later). (#3349)
-- Selectable: Fixed highlight/hit extent when used with horizontal scrolling (in or outside columns). 
+- Selectable: Fixed highlight/hit extent when used with horizontal scrolling (in or outside columns).
   Also fixed related text clipping when used in a column after the first one. (#3187, #3386)
 - Scrolling: Avoid SetScroll, SetScrollFromPos functions from snapping on the edge of scroll
   limits when close-enough by (WindowPadding - ItemPadding), which was a tweak with too many
@@ -80,6 +80,8 @@ Other Changes:
 - Demo: Improved "Layout & Scrolling" -> "Child Windows" section.
 - Style Editor: Added preview of circle auto-tessellation when editing the corresponding value.
 - Backends: OpenGL3: Added support for glad2 loader. (#3330) [@moritz-h]
+- Backends: Allegro 5: Fixed horizontal scrolling direction with mouse wheel / touch pads (it seems
+  like Allegro 5 reports it differently from GLFW and SDL). (#3394, #2424, #1463) [@nobody-special666]
 - Examples: Vulkan: Fixed GLFW+Vulkan and SDL+Vulkan clear color not being set. (#3390) [@RoryO]
 
 
diff --git a/examples/example_allegro5/example_allegro5.vcxproj b/examples/example_allegro5/example_allegro5.vcxproj
index c86dcb2bc..f5fadc37f 100644
--- a/examples/example_allegro5/example_allegro5.vcxproj
+++ b/examples/example_allegro5/example_allegro5.vcxproj
@@ -19,7 +19,7 @@
     </ProjectConfiguration>
   </ItemGroup>
   <PropertyGroup Label="Globals">
-    <ProjectGuid>{2AE17FDE-F7F3-4CAC-ADAB-0710EDA4F741}</ProjectGuid>
+    <ProjectGuid>{73F235B5-7D31-4FC6-8682-DDC5A097B9C1}</ProjectGuid>
     <RootNamespace>example_allegro5</RootNamespace>
     <WindowsTargetPlatformVersion>8.1</WindowsTargetPlatformVersion>
   </PropertyGroup>
diff --git a/examples/imgui_impl_allegro5.cpp b/examples/imgui_impl_allegro5.cpp
index 4a467c30d..ca2cfae46 100644
--- a/examples/imgui_impl_allegro5.cpp
+++ b/examples/imgui_impl_allegro5.cpp
@@ -15,6 +15,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2020-08-10: Inputs: Fixed horizontal mouse wheel direction.
 //  2019-12-05: Inputs: Added support for ImGuiMouseCursor_NotAllowed mouse cursor.
 //  2019-07-21: Inputs: Added mapping for ImGuiKey_KeyPadEnter.
 //  2019-05-11: Inputs: Don't filter character value from ALLEGRO_EVENT_KEY_CHAR before calling AddInputCharacter().
@@ -332,7 +333,7 @@ bool ImGui_ImplAllegro5_ProcessEvent(ALLEGRO_EVENT* ev)
         if (ev->mouse.display == g_Display)
         {
             io.MouseWheel += ev->mouse.dz;
-            io.MouseWheelH += ev->mouse.dw;
+            io.MouseWheelH -= ev->mouse.dw;
             io.MousePos = ImVec2(ev->mouse.x, ev->mouse.y);
         }
         return true;