anchor.diff:    Groups.PagesCurrent.Tabs.SwitchTab(ANext);
   end;
   
  -function TfmMain.DoCheckFilenameOpened(const AName: string): boolean;
  -var
  -  SName: string;
  +function TfmMain.FindFrameOfFilename(const AName: string): TEditorFrame;
  +var
  +  F: TEditorFrame;
     i: integer;
   begin
  -  Result:= false;
  +  Result:= nil;
     if AName='' then exit;
     for i:= 0 to FrameCount-1 do
     begin
  -    SName:= Frames[i].FileName;
  -    if SameFileName(SName, AName) then exit(true);
  -  end;
  +    F:= Frames[i];
  +    if SameFileName(AName, F.GetFileName(F.Ed1)) or
  +      SameFileName(AName, F.GetFileName(F.Ed2)) then exit(F);
  +  end;
  +end;
  +
  +
  +function TfmMain.DoCheckFilenameOpened(const AName: string): boolean;
  +begin
  +  Result:= Assigned(FindFrameOfFilename(AName));
   end;
   
   procedure TfmMain.DoOps_OpenFile_Default;
  
positive.code:       AIndex: integer; const ARect: TRect);
      procedure DoSidebar_MainMenuClick(Sender: TObject);
      function DoSidebar_TranslatedCaption(const ACaption: string): string;
      procedure FixMainLayout;
      procedure FormFloatBottomOnClose(Sender: TObject; var CloseAction: TCloseAction);
      procedure FormFloatGroups1_OnEmpty(Sender: TObject);
  
negative.code:   end; //not binary
  
    //is file already opened? activate frame
    F:= FindFrameOfFilename(AFileName);
    if F=nil then
      F:= FindFrameOfFilename(AFileName2);
    if Assigned(F) then
    begin
      SetFrame(F);
      Result:= F;
      Result.SetFocus;
      UpdateStatus;
      UpdateTreeContents;
      Exit
    end;
  
    //preview-tab
  