[KOE-125] Fixed mouse wheel handling for combo box

src/AcaciaZPushPlugin/AcaciaZPushPlugin/Controls/KComboBox.cs

@@ -381,5 +381,17 @@ namespace Acacia.Controls
                     break;
             }
         }
+
+        protected override void DefWndProc(ref Message m)
+        {
+            switch ((WM)m.Msg)
+            {
+                // Forward mouse wheel messages to the list
+                case WM.MOUSEWHEEL:
+                    m.Result = (IntPtr) User32.SendMessage(_list.Handle, m.Msg, m.WParam, m.LParam);
+                    return;
+            }
+            base.DefWndProc(ref m);
+        }
     }
 }

src/AcaciaZPushPlugin/AcaciaZPushPlugin/Native/WM.cs

@@ -45,7 +45,9 @@ namespace Acacia.Native
 
         LBUTTONDOWN = 0x0201,
         RBUTTONDOWN = 0x0204,
-        MBUTTONDOWN = 0x0207
+        MBUTTONDOWN = 0x0207,
+
+        MOUSEWHEEL = 0x020A,
 
     }
 }