diff --git a/lcl/interfaces/win32/win32wscontrols.pp b/lcl/interfaces/win32/win32wscontrols.pp
index eff8bf0732..5219a0b925 100644
--- a/lcl/interfaces/win32/win32wscontrols.pp
+++ b/lcl/interfaces/win32/win32wscontrols.pp
@@ -206,6 +206,12 @@ begin
         end;
       end;
 
+      // mantis #26206: Layered windows are only supported for top-level windows.
+      // After Windows 8 it is supported for child windows too.
+      if (WindowsVersion < wv8) and Assigned(AWinControl.Parent)
+      and (AWinControl is TCustomForm) and TCustomForm(AWinControl).AlphaBlend then
+        FlagsEx := FlagsEx and not WS_EX_LAYERED;
+
       Window := CreateWindowExW(FlagsEx, PWideChar(WideString(pClassName)),
         PWideChar(UTF8ToUTF16(WindowTitle)), Flags,
         Left, Top, Width, Height, Parent, 0, HInstance, @NCCreateParams);