TMemo running into error when applying styles in Python x64. Ref: Embarcadero/DelphiVCL4Python#18

Author: lmbelo

Source/vcl/WrapVclThemes.pas

@@ -88,7 +88,24 @@   TStyleManagerStyleNamesAccess = class(TContainerAccess)
 implementation
 
 uses
-  System.SysUtils, Vcl.Controls, MethodCallBack;
+  System.SysUtils, System.Rtti, Vcl.Controls, Vcl.StdCtrls, Vcl.Forms, MethodCallBack;
+
+type
+  //https://github.com/Embarcadero/DelphiVCL4Python/issues/18
+  TMemoStyleHookWA18 = class(TMemoStyleHook)
+  strict private
+    FParent: TScrollingStyleHook;
+  strict protected
+    procedure WndProc(var Message: TMessage); override;
+  public
+    constructor Create(AControl: TWinControl); override;
+    destructor Destroy; override;
+  end;
+
+  TScrollingStyleHookCrackerWA18 = class(TScrollingStyleHook)
+  protected
+    procedure WndProc(var Message: TMessage); override;
+  end;
 
 { Global Functions }
 
@@ -510,7 +527,43 @@ class procedure TPyDelphiCustomStyleServices.RegisterMethods(
   inherited;
 end;
 
+{ TMemoStyleHookWA18 }
+
+constructor TMemoStyleHookWA18.Create(AControl: TWinControl);
+begin
+  inherited;
+  FParent := TScrollingStyleHook.Create(AControl);
+end;
+
+destructor TMemoStyleHookWA18.Destroy;
+begin
+  FParent.Free();
+  inherited;
+end;
+
+procedure TMemoStyleHookWA18.WndProc(var Message: TMessage);
+begin
+  case Message.Msg of
+    WM_ERASEBKGND:
+    begin
+      TScrollingStyleHookCrackerWA18(FParent).WndProc(Message);
+    end;
+    else inherited;
+  end;
+end;
+
+{ TScrollingStyleHookCrackWA18 }
+
+procedure TScrollingStyleHookCrackerWA18.WndProc(var Message: TMessage);
+begin
+  inherited;
+end;
+
 initialization
   RegisteredUnits.Add(TVclThemesRegistration.Create());
+  TCustomStyleEngine.RegisterStyleHook(TMemo, TMemoStyleHookWA18);
+
+finalization
+  TCustomStyleEngine.UnRegisterStyleHook(TMemo, TMemoStyleHookWA18);
 
 end.