private static void SetAccentPolicy(Form window, PI.AccentState accentState) { // var windowHelper = new WindowInteropHelper(window); PI.AccentPolicy accent = new PI.AccentPolicy { AccentState = accentState, AccentFlags = GetAccentFlagsForTaskbarPosition() }; int accentStructSize = Marshal.SizeOf(accent); IntPtr accentPtr = Marshal.AllocHGlobal(accentStructSize); Marshal.StructureToPtr(accent, accentPtr, false); PI.WindowCompositionAttribData data = new PI.WindowCompositionAttribData { Attribute = PI.WindowCompositionAttribute.WCA_ACCENT_POLICY, SizeOfData = accentStructSize, Data = accentPtr }; PI.SetWindowCompositionAttribute(window.Handle, ref data); Marshal.FreeHGlobal(accentPtr); }