Added QT6 support

Added SimpleBrowser for Lazarus and QT6

demos/Lazarus_Linux_QT6/SimpleBrowser/00-Delete.bat

@@ -0,0 +1,2 @@
+rmdir /S /Q lib
+rmdir /S /Q backup

demos/Lazarus_Linux_QT6/SimpleBrowser/SimpleBrowser.lpi

@@ -0,0 +1,98 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<CONFIG>
+  <ProjectOptions>
+    <Version Value="12"/>
+    <General>
+      <SessionStorage Value="InProjectDir"/>
+      <Title Value="SimpleBrowser"/>
+      <Scaled Value="True"/>
+      <ResourceType Value="res"/>
+      <UseXPManifest Value="True"/>
+      <XPManifest>
+        <DpiAware Value="True"/>
+      </XPManifest>
+      <Icon Value="0"/>
+    </General>
+    <MacroValues Count="1">
+      <Macro1 Name="LCLWidgetType" Value="qt6"/>
+    </MacroValues>
+    <BuildModes>
+      <Item Name="Default" Default="True"/>
+      <SharedMatrixOptions Count="1">
+        <Item1 ID="204233492819" Modes="Default" Type="IDEMacro" MacroName="LCLWidgetType" Value="qt6"/>
+      </SharedMatrixOptions>
+    </BuildModes>
+    <PublishOptions>
+      <Version Value="2"/>
+      <UseFileFilters Value="True"/>
+    </PublishOptions>
+    <RunParams>
+      <FormatVersion Value="2"/>
+    </RunParams>
+    <RequiredPackages>
+      <Item>
+        <PackageName Value="CEF4Delphi_Lazarus"/>
+      </Item>
+      <Item>
+        <PackageName Value="LCL"/>
+      </Item>
+    </RequiredPackages>
+    <Units>
+      <Unit>
+        <Filename Value="SimpleBrowser.lpr"/>
+        <IsPartOfProject Value="True"/>
+      </Unit>
+      <Unit>
+        <Filename Value="umainform.pas"/>
+        <IsPartOfProject Value="True"/>
+        <ComponentName Value="MainForm"/>
+        <HasResources Value="True"/>
+        <ResourceBaseClass Value="Form"/>
+        <UnitName Value="uMainForm"/>
+      </Unit>
+      <Unit>
+        <Filename Value="interfaces.pas"/>
+        <IsPartOfProject Value="True"/>
+      </Unit>
+    </Units>
+  </ProjectOptions>
+  <CompilerOptions>
+    <Version Value="11"/>
+    <Target>
+      <Filename Value="../../../bin/SimpleBrowser"/>
+    </Target>
+    <SearchPaths>
+      <IncludeFiles Value="$(ProjOutDir)"/>
+      <UnitOutputDirectory Value="lib/$(TargetCPU)-$(TargetOS)"/>
+    </SearchPaths>
+    <Linking>
+      <Debugging>
+        <DebugInfoType Value="dsDwarf3"/>
+      </Debugging>
+      <Options>
+        <Win32>
+          <GraphicApplication Value="True"/>
+        </Win32>
+      </Options>
+    </Linking>
+    <Other>
+      <CustomOptions Value="-dUseCThreads"/>
+      <OtherDefines Count="1">
+        <Define0 Value="UseCThreads"/>
+      </OtherDefines>
+    </Other>
+  </CompilerOptions>
+  <Debugging>
+    <Exceptions>
+      <Item>
+        <Name Value="EAbort"/>
+      </Item>
+      <Item>
+        <Name Value="ECodetoolError"/>
+      </Item>
+      <Item>
+        <Name Value="EFOpenError"/>
+      </Item>
+    </Exceptions>
+  </Debugging>
+</CONFIG>

demos/Lazarus_Linux_QT6/SimpleBrowser/SimpleBrowser.lpr

@@ -0,0 +1,42 @@
+program SimpleBrowser;
+
+{$mode objfpc}{$H+}
+
+uses
+  {$IFDEF UNIX}
+  cthreads,
+  {$ENDIF}
+  {$IFDEF HASAMIGA}
+  athreads,
+  {$ENDIF}
+  Interfaces, // this includes the LCL widgetset
+  Forms, uMainForm
+  { you can add units after this },
+  uCEFApplication;
+
+{$R *.res}
+
+begin
+  CreateGlobalCEFApp;
+
+  if StartMainProcess then
+    begin
+      // The LCL Widgetset must be initialized after the CEF initialization and
+      // only in the browser process.
+      CustomWidgetSetInitialization;
+
+      RequireDerivedFormResource:=True;
+      Application.Scaled:=True;
+      {$PUSH}{$WARN 5044 OFF}
+      Application.MainFormOnTaskbar:=True;
+      {$POP}
+      Application.Initialize;
+      Application.CreateForm(TMainForm, MainForm);
+      Application.Run;
+
+      CustomWidgetSetFinalization;
+    end;
+
+  DestroyGlobalCEFApp;
+end.
+

demos/Lazarus_Linux_QT6/SimpleBrowser/interfaces.pas

@@ -0,0 +1,66 @@
+{
+ /***************************************************************************
+                         Interfaces.pp  -  determines what interface to use
+                             -------------------
+
+                   Initial Revision  : Thu July 1st CST 1999
+
+
+ ***************************************************************************/
+
+ *****************************************************************************
+  This file is part of the Lazarus Component Library (LCL)
+
+  See the file COPYING.modifiedLGPL.txt, included in this distribution,
+  for details about the license.
+ *****************************************************************************
+}
+
+unit interfaces;
+
+{$mode objfpc}
+{$H+}
+
+interface
+
+uses
+  {$IFDEF UNIX}{$IFNDEF DisableCWString}cwstring,{$ENDIF}{$ENDIF}
+  InterfaceBase;
+
+procedure CustomWidgetSetInitialization;
+procedure CustomWidgetSetFinalization;
+
+implementation
+
+uses
+  qtint, Forms, xlib;
+
+function CustomX11ErrorHandler(Display:PDisplay; ErrorEv:PXErrorEvent):longint;cdecl;
+begin
+  {$IFDEF DEBUG}
+  XError := ErrorEv^.error_code;
+  WriteLn('Error: ' + IntToStr(XError));
+  {$ENDIF}
+  Result := 0;
+end;
+
+function CustomXIOErrorHandler(Display:PDisplay):longint;cdecl;
+begin
+  Result := 0;
+end;
+
+procedure CustomWidgetSetInitialization;
+begin
+  CreateWidgetset(TQtWidgetSet);
+  // Install xlib error handlers so that the application won't be terminated
+  // on non-fatal errors. Must be done after initializing QT.
+  XSetErrorHandler(@CustomX11ErrorHandler);
+  XSetIOErrorHandler(@CustomXIOErrorHandler);
+end;
+
+procedure CustomWidgetSetFinalization;
+begin
+  FreeWidgetSet;
+end;
+
+end.

demos/Lazarus_Linux_QT6/SimpleBrowser/umainform.lfm

@@ -0,0 +1,124 @@
+object MainForm: TMainForm
+  Left = 342
+  Height = 768
+  Top = 31
+  Width = 1024
+  Caption = 'Simple Browser. Initializing...'
+  ClientHeight = 768
+  ClientWidth = 1024
+  Position = poScreenCenter
+  OnActivate = FormActivate
+  OnCloseQuery = FormCloseQuery
+  OnCreate = FormCreate
+  object CEFLinkedWindowParent1: TCEFLinkedWindowParent
+    Left = 0
+    Height = 742
+    Top = 26
+    Width = 1024
+    Align = alClient
+    TabStop = True
+    TabOrder = 1
+    OnEnter = CEFLinkedWindowParent1Enter
+    OnExit = CEFLinkedWindowParent1Exit
+    Chromium = Chromium1
+  end
+  object AddressPnl: TPanel
+    Left = 0
+    Height = 26
+    Top = 0
+    Width = 1024
+    Align = alTop
+    BevelOuter = bvNone
+    ClientHeight = 26
+    ClientWidth = 1024
+    TabOrder = 0
+    object AddressCb: TComboBox
+      Left = 0
+      Height = 26
+      Top = 0
+      Width = 965
+      Align = alClient
+      ItemHeight = 0
+      ItemIndex = 0
+      Items.Strings = (
+        'https://www.google.com'
+        'https://www.bing.com'
+        'https://duckduckgo.com'
+        'https://www.qwant.com'
+        'https://yandex.com'
+        'https://www.startpage.com'
+        'https://www.ecosia.org'
+        'https://www.baidu.com'
+        'https://www.whatismybrowser.com/detect/what-http-headers-is-my-browser-sending'
+        'https://www.w3schools.com/js/tryit.asp?filename=tryjs_win_close'
+        'https://www.w3schools.com/js/tryit.asp?filename=tryjs_alert'
+        'https://www.w3schools.com/js/tryit.asp?filename=tryjs_loc_assign'
+        'https://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_style_backgroundcolor'
+        'https://www.w3schools.com/Tags/tryit.asp?filename=tryhtml_iframe_name'
+        'https://www.w3schools.com/tags/tryit.asp?filename=tryhtml5_input_type_file'
+        'https://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_state_throw_error'
+        'https://www.htmlquick.com/es/reference/tags/input-file.html'
+        'https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/file'
+        'https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement/webkitdirectory'
+        'https://www.w3schools.com/html/html5_video.asp'
+        'http://html5test.com/'
+        'https://webrtc.github.io/samples/src/content/devices/input-output/'
+        'https://test.webrtc.org/'
+        'https://www.browserleaks.com/webrtc'
+        'https://shaka-player-demo.appspot.com/demo/'
+        'http://webglsamples.org/'
+        'https://get.webgl.org/'
+        'https://www.briskbard.com'
+        'https://www.youtube.com'
+        'https://html5demos.com/drag/'
+        'https://frames-per-second.appspot.com/'
+        'https://www.sede.fnmt.gob.es/certificados/persona-fisica/verificar-estado'
+        'https://www.kirupa.com/html5/accessing_your_webcam_in_html5.htm'
+        'https://www.xdumaine.com/enumerateDevices/test/'
+        'https://dagrs.berkeley.edu/sites/default/files/2020-01/sample.pdf'
+        'https://codepen.io/udaymanvar/pen/MWaePBY'
+        'https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/accept'
+        'chrome://version/'
+        'chrome://net-internals/'
+        'chrome://tracing/'
+        'chrome://appcache-internals/'
+        'chrome://blob-internals/'
+        'chrome://view-http-cache/'
+        'chrome://credits/'
+        'chrome://histograms/'
+        'chrome://media-internals/'
+        'chrome://kill'
+        'chrome://crash'
+        'chrome://hang'
+        'chrome://shorthang'
+        'chrome://gpuclean'
+        'chrome://gpucrash'
+        'chrome://gpuhang'
+        'chrome://extensions-support'
+        'chrome://process-internals'
+      )
+      TabOrder = 0
+      Text = 'https://www.google.com'
+    end
+    object GoBtn: TButton
+      Left = 965
+      Height = 26
+      Top = 0
+      Width = 59
+      Align = alRight
+      Caption = 'Go'
+      TabOrder = 1
+      OnClick = GoBtnClick
+    end
+  end
+  object Chromium1: TChromium
+    OnGotFocus = Chromium1GotFocus
+    OnBeforePopup = Chromium1BeforePopup
+    OnAfterCreated = Chromium1AfterCreated
+    OnBeforeClose = Chromium1BeforeClose
+    OnClose = Chromium1Close
+    OnOpenUrlFromTab = Chromium1OpenUrlFromTab
+    Left = 106
+    Top = 69
+  end
+end

demos/Lazarus_Linux_QT6/SimpleBrowser/umainform.pas

@@ -0,0 +1,296 @@
+unit uMainForm;
+
+{$mode objfpc}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils, Forms, Controls, Graphics, SyncObjs, Dialogs, ExtCtrls,
+  LMessages, StdCtrls,
+  uCEFChromium, uCEFLinkedWindowParent, uCEFInterfaces, uCEFChromiumEvents,
+  uCEFTypes;
+            
+const
+  CEF_SETFOCUS = 1;
+
+type
+  { TMainForm }
+
+  TMainForm = class(TForm)
+    GoBtn: TButton;
+    CEFLinkedWindowParent1: TCEFLinkedWindowParent;
+    Chromium1: TChromium;
+    AddressCb: TComboBox;
+    AddressPnl: TPanel;
+
+    procedure Chromium1AfterCreated(Sender: TObject; const browser: ICefBrowser);
+    procedure Chromium1BeforeClose(Sender: TObject; const browser: ICefBrowser);
+    procedure Chromium1BeforePopup(Sender: TObject; const browser: ICefBrowser; const frame: ICefFrame; popup_id: Integer; const targetUrl, targetFrameName: ustring; targetDisposition: TCefWindowOpenDisposition; userGesture: Boolean; const popupFeatures: TCefPopupFeatures; var windowInfo: TCefWindowInfo; var client: ICefClient; var settings: TCefBrowserSettings; var extra_info: ICefDictionaryValue; var noJavascriptAccess: Boolean; var Result: Boolean);
+    procedure Chromium1Close(Sender: TObject; const browser: ICefBrowser; var aAction: TCefCloseBrowserAction);
+    procedure Chromium1GotFocus(Sender: TObject; const browser: ICefBrowser);
+    procedure Chromium1OpenUrlFromTab(Sender: TObject; const browser: ICefBrowser; const frame: ICefFrame; const targetUrl: ustring; targetDisposition: TCefWindowOpenDisposition; userGesture: Boolean; out Result: Boolean);
+
+    procedure FormActivate(Sender: TObject);
+    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
+    procedure FormCreate(Sender: TObject);
+
+    procedure GoBtnClick(Sender: TObject);        
+    procedure CEFLinkedWindowParent1Enter(Sender: TObject);
+    procedure CEFLinkedWindowParent1Exit(Sender: TObject);
+  private   
+
+  protected
+    // Variables to control when can we destroy the form safely
+    FCanClose  : boolean;  // Set to True in TChromium.OnBeforeClose
+    FClosing   : boolean;  // Set to True in the CloseQuery event.
+
+    // CEF needs to handle these messages to call TChromium.NotifyMoveOrResizeStarted
+    procedure WMMove(var Message: TLMMove); message LM_MOVE;
+    procedure WMSize(var Message: TLMSize); message LM_SIZE;
+    procedure WMWindowPosChanged(var Message: TLMWindowPosChanged); message LM_WINDOWPOSCHANGED;
+
+    procedure SendCompMessage(aMsg : cardinal; aData: PtrInt = 0);
+
+    procedure BrowserCreatedMsg(Data: PtrInt);
+    procedure BrowserCloseFormMsg(Data: PtrInt);
+    procedure BrowserSetFocusMsg(Data: PtrInt);
+
+  public
+
+  end;
+
+var
+  MainForm: TMainForm;
+                           
+procedure CreateGlobalCEFApp;
+function StartMainProcess: boolean;
+
+implementation
+
+{$R *.lfm}
+
+uses
+  Math,  
+  uCEFMiscFunctions, uCEFApplication, uCEFLinuxFunctions, uCEFConstants;
+
+var
+  MainAppEvent : TEventObject;
+
+{GlobalCEFApp functions}
+{%Region}
+procedure GlobalCEFApp_OnContextInitialized();
+begin
+  MainAppEvent.SetEvent;
+end;
+
+procedure CreateGlobalCEFApp;
+begin
+  GlobalCEFApp                            := TCefApplication.Create;  
+  GlobalCEFApp.LogFile                    := 'debug.log';
+  GlobalCEFApp.LogSeverity                := LOGSEVERITY_INFO;
+  GlobalCEFApp.RootCache                  := 'RootCache';
+  GlobalCEFApp.SetCurrentDir              := True;                             
+  GlobalCEFApp.DisableZygote              := True;
+  GlobalCEFApp.OnContextInitialized       := @GlobalCEFApp_OnContextInitialized;
+end;
+
+function StartMainProcess: boolean;
+begin
+  Result := False;
+
+  if GlobalCEFApp.StartMainProcess then
+    begin
+      // Wait until the context is initialized before initializing GTK.
+      if (MainAppEvent.WaitFor(10000) = wrTimeout) then
+        CefDebugLog('CEF initialization failure!')
+       else
+        Result := True;
+    end;
+end;    
+{%Endregion}
+
+{TForm events}
+{%Region}
+procedure TMainForm.FormCreate(Sender: TObject);
+begin                             
+  FCanClose   := False;
+  FClosing    := False;
+
+  // CEF requires a native widget
+  CEFLinkedWindowParent1.SetQTWidgetAsNative;
+
+  Chromium1.DefaultURL := UTF8Decode(AddressCb.Text);
+end;
+
+procedure TMainForm.FormActivate(Sender: TObject);
+var
+  TempRect : TRect;
+begin
+  TempRect := Rect(0, 0, CEFLinkedWindowParent1.Width, CEFLinkedWindowParent1.Height);
+  Chromium1.CreateBrowser(CEFLinkedWindowParent1.Handle, TempRect);
+end;
+
+procedure TMainForm.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
+begin
+  if not Chromium1.Initialized then
+    begin
+      FCanClose := True;
+      FClosing  := True;
+    end;
+
+  CanClose := FCanClose;
+
+  if not(FClosing) then
+    begin
+      FClosing := True;
+      Visible  := False;
+      Chromium1.CloseBrowser(True);
+
+      if Chromium1.RuntimeStyle = CEF_RUNTIME_STYLE_CHROME then
+        CEFLinkedWindowParent1.Free;
+    end;
+end;
+{%Endregion}
+
+{TCEFLinkedWindowParent events}
+{%Region}
+procedure TMainForm.CEFLinkedWindowParent1Enter(Sender: TObject);
+begin
+  if not(csDesigning in ComponentState) and
+     Chromium1.Initialized and
+     not(Chromium1.FrameIsFocused) then
+    Chromium1.SetFocus(True);
+end;
+
+// This is a workaround for the CEF issue #2026
+// https://bitbucket.org/chromiumembedded/cef/issues/2026/multiple-major-keyboard-focus-issues-on
+// We use CEFLinkedWindowParent1.OnEnter, CEFLinkedWindowParent1.OnExit and
+// TChromium.OnGotFocus to avoid most of the focus issues.
+// CEFLinkedWindowParent1.TabStop must be TRUE.
+procedure TMainForm.CEFLinkedWindowParent1Exit(Sender: TObject);
+begin
+  if not(csDesigning in ComponentState) then
+    Chromium1.SendCaptureLostEvent;
+end;
+{%Endregion}
+
+{Message handlers}
+{%Region}
+procedure TMainForm.BrowserCreatedMsg(Data: PtrInt);
+begin
+  Caption            := 'Simple Browser';
+  AddressPnl.Enabled := True;
+  Chromium1.UpdateXWindowVisibility(True);
+  CEFLinkedWindowParent1.UpdateSize;
+  CEFLinkedWindowParent1.InvalidateChildren;
+end;
+
+procedure TMainForm.BrowserCloseFormMsg(Data: PtrInt);
+begin
+  Close;
+end;
+
+procedure TMainForm.BrowserSetFocusMsg(Data: PtrInt);
+begin
+  CEFLinkedWindowParent1.SetFocus;
+end;
+
+procedure TMainForm.WMMove(var Message: TLMMove);
+begin
+  inherited;
+  Chromium1.NotifyMoveOrResizeStarted;
+end;
+
+procedure TMainForm.WMSize(var Message: TLMSize);
+begin
+  inherited;
+  Chromium1.NotifyMoveOrResizeStarted;
+end;
+
+procedure TMainForm.WMWindowPosChanged(var Message: TLMWindowPosChanged);
+begin
+  inherited;
+  Chromium1.NotifyMoveOrResizeStarted;
+end;
+{%Endregion}  
+
+{Misc functions}
+{%Region}
+procedure TMainForm.SendCompMessage(aMsg : cardinal; aData: PtrInt);
+begin
+  case aMsg of
+    CEF_AFTERCREATED : Application.QueueAsyncCall(@BrowserCreatedMsg, 0);
+    CEF_BEFORECLOSE  : Application.QueueAsyncCall(@BrowserCloseFormMsg, 0);
+    CEF_SETFOCUS     : Application.QueueAsyncCall(@BrowserSetFocusMsg, 0);
+  end;
+end;    
+
+procedure TMainForm.GoBtnClick(Sender: TObject);
+begin
+  Chromium1.LoadURL(UTF8Decode(AddressCb.Text));
+end;
+{%Endregion}
+
+{TChromium events}
+{%Region}
+procedure TMainForm.Chromium1AfterCreated(Sender: TObject;
+  const browser: ICefBrowser);
+begin
+  // Now the browser is fully initialized we can initialize the UI.
+  SendCompMessage(CEF_AFTERCREATED);
+end;
+
+procedure TMainForm.Chromium1BeforeClose(Sender: TObject;
+  const browser: ICefBrowser);
+begin
+  // We must wait until all browsers trigger the TChromium.OnBeforeClose event
+  // in order to close the application safely or we will have shutdown issues.
+  FCanClose := True;
+  SendCompMessage(CEF_BEFORECLOSE);
+end;
+
+procedure TMainForm.Chromium1BeforePopup(Sender: TObject;
+  const browser: ICefBrowser; const frame: ICefFrame; popup_id: Integer;
+  const targetUrl, targetFrameName: ustring;
+  targetDisposition: TCefWindowOpenDisposition; userGesture: Boolean;
+  const popupFeatures: TCefPopupFeatures; var windowInfo: TCefWindowInfo;
+  var client: ICefClient; var settings: TCefBrowserSettings;
+  var extra_info: ICefDictionaryValue; var noJavascriptAccess: Boolean;
+  var Result: Boolean);
+begin
+  // For simplicity, this demo blocks all popup windows and new tabs
+  Result := (targetDisposition in [CEF_WOD_NEW_FOREGROUND_TAB, CEF_WOD_NEW_BACKGROUND_TAB, CEF_WOD_NEW_POPUP, CEF_WOD_NEW_WINDOW]);
+end;
+
+procedure TMainForm.Chromium1Close(Sender: TObject; const browser: ICefBrowser;
+  var aAction: TCefCloseBrowserAction);
+begin
+  // continue closing the browser
+  aAction := cbaClose;
+end;
+
+procedure TMainForm.Chromium1GotFocus(Sender: TObject;
+  const browser: ICefBrowser);
+begin   
+  SendCompMessage(CEF_SETFOCUS);
+end;
+
+procedure TMainForm.Chromium1OpenUrlFromTab(Sender: TObject;
+  const browser: ICefBrowser; const frame: ICefFrame; const targetUrl: ustring;
+  targetDisposition: TCefWindowOpenDisposition; userGesture: Boolean; out
+  Result: Boolean);
+begin
+  // For simplicity, this demo blocks all popup windows and new tabs
+  Result := (targetDisposition in [CEF_WOD_NEW_FOREGROUND_TAB, CEF_WOD_NEW_BACKGROUND_TAB, CEF_WOD_NEW_POPUP, CEF_WOD_NEW_WINDOW]);
+end;      
+{%Endregion}
+
+initialization
+  MainAppEvent := TEventObject.Create(nil, True, False, 'MainAppEvent');
+
+finalization
+  if assigned(MainAppEvent) then
+    FreeAndNil(MainAppEvent);
+
+end.
+

source/uCEFChromiumCore.pas

@@ -4246,6 +4246,9 @@ uses
       {$IFDEF LINUX}x, xatom,
         {$IFDEF LCLGTK2}gdk2x, gtk2,{$ENDIF}
         {$IFDEF LCLGTK3}LazGdk3, LazGtk3, LazGLib2,{$ENDIF}
+        {$IFDEF LCLQT}qt4,{$ENDIF}
+        {$IFDEF LCLQT5}qt5,{$ENDIF}
+        {$IFDEF LCLQT6}qtint,{$ENDIF}
       {$ENDIF}
     {$ENDIF}
   {$ENDIF}
@@ -5887,7 +5890,7 @@ end;
 
 {$IFDEF LINUX}
 function TChromiumCore.GetXDisplay : PXDisplay;
-{$IFDEF FPC}
+{$IFDEF LCLGTK2}
 var
   TempParent : TCefWindowHandle;
 {$ENDIF}
@@ -5903,13 +5906,14 @@ begin
           FXDisplay := GDK_WINDOW_XDISPLAY(PGtkWidget(TempParent)^.Window);
         {$ENDIF}
         {$IFDEF LCLGTK3}
-        TempParent := ParentFormHandle;
-        {
-        if ValidCefWindowHandle(TempParent) and
-           (PGtkWidget(TempParent)^.Window <> nil) then
-          FXDisplay := GDK_WINDOW_XDISPLAY(PGtkWidget(TempParent)^.Window);  }
         FXDisplay := gdk_x11_get_default_xdisplay();
         {$ENDIF}
+        {$IF DEFINED(LCLQT) OR DEFINED(LCLQT5)}
+        FXDisplay := QX11Info_display();
+        {$IFEND}
+        {$IFDEF LCLQT6}
+        FXDisplay := TQtWidgetSet(WidgetSet).x11Display;  
+        {$ENDIF}
       {$ENDIF}
 
       // GlobalCEFApp.XDisplay can only be called in the CEF UI thread.

source/uCEFLinkedWinControlBase.pas

@@ -187,7 +187,13 @@ begin
   if not(csDesigning in ComponentState) and
      (Chromium <> nil) and
      Chromium.Initialized then
+    begin
+      {$IF DEFINED(LCLQT) OR DEFINED(LCLQT5) OR DEFINED(LCLQT6)}
+      Chromium.UpdateBrowserSize(0, 0, Width, Height);
+      {$ELSE}
       Chromium.UpdateBrowserSize(Left, Top, Width, Height);
+      {$IFEND}
+    end;
   {$ENDIF}
 
   {$IFDEF MACOSX}

source/uCEFWinControl.pas

@@ -59,6 +59,12 @@ type
       /// Updates the size of the child windows created by the browser.
       /// </summary>
       procedure   UpdateSize; virtual;
+      {$IF DEFINED(LCLQT) OR DEFINED(LCLQT5) OR DEFINED(LCLQT6)}
+      /// <summary>
+      /// Set this widget as native with a native window handle.
+      /// </summary>
+      procedure   SetQTWidgetAsNative;
+      {$IFEND}
       /// <summary>
       /// Handle of the first child window created by the browser.
       /// </summary>
@@ -101,6 +107,9 @@ type
 implementation
 
 uses
+  {$IFDEF LCLQT}qtwidgets, qt4,{$ENDIF}
+  {$IFDEF LCLQT5}qtwidgets, qt5,{$ENDIF}
+  {$IFDEF LCLQT6}qtwidgets, qt6,{$ENDIF}
   uCEFMiscFunctions, uCEFClient, uCEFConstants;
 
 function TCEFWinControl.GetChildWindowHandle : {$IFNDEF MSWINDOWS}{$IFDEF FPC}LclType.{$ENDIF}{$ENDIF}THandle;
@@ -118,6 +127,14 @@ begin
   inherited CreateHandle;
 end;
 
+{$IF DEFINED(LCLQT) OR DEFINED(LCLQT5) OR DEFINED(LCLQT6)}
+procedure TCEFWinControl.SetQTWidgetAsNative;
+begin
+  TQtWidget(Handle).setAttribute(QtWA_NativeWindow); // This widget becomes native...
+  TQtWidget(Handle).setAttribute(QtWA_DontCreateNativeAncestors); // ...but not the ancestors.
+end;
+{$IFEND}
+
 procedure TCEFWinControl.InvalidateChildren;
 begin
   if HandleAllocated then

source/uCEFWindowInfoWrapper.pas

@@ -538,6 +538,7 @@ begin
     {$IF DEFINED(LCLQT) OR DEFINED(LCLQT5) OR DEFINED(LCLQT6)}
     if ValidCefWindowHandle(aParent) then
       begin
+        // CEF requires a native widget with an associated native window handle.
         TempParent := QWidget_winId(TQtWidget(aParent).Widget);
       end;
     {$IFEND}

update_CEF4Delphi.json

@@ -2,7 +2,7 @@
   "UpdateLazPackages" : [
     {
       "ForceNotify" : true,
-      "InternalVersion" : 784,
+      "InternalVersion" : 785,
       "Name" : "cef4delphi_lazarus.lpk",
       "Version" : "139.0.40"
     }