diff --git a/Constants.cs b/Constants.cs
index 8d7df85..2019d69 100644
--- a/Constants.cs
+++ b/Constants.cs
@@ -104,6 +104,9 @@ namespace Common.Native
             DwmCompositionChanged = 0x031e,
             User = 0x0400,
             App = 0x8000,
+
+            EnterSizeMove = 0x0231,
+            ExitSizeMove = 0x0232
         }
 
         public enum HitTestValues
diff --git a/Functions.cs b/Functions.cs
index 4262dc0..88f3b17 100644
--- a/Functions.cs
+++ b/Functions.cs
@@ -155,6 +155,9 @@ namespace Common.Native
             [DllImport("user32.dll")]
             public static extern IntPtr SetWindowLongPtr(IntPtr hWnd, int nIndex, IntPtr dwNewLong);
 
+            [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
+            public static extern uint RegisterWindowMessage(string lpString);
+
             public static IntPtr SetWindowLongPtrSmart(IntPtr hWnd, int nIndex, IntPtr dwNewLong)
             {
                 if (IntPtr.Size == 8)