Вопрос:
Как изменить шрифта hint'а?
Ответ:
В примере перехватывается событие Application.OnShowHint и изменяется шрифт Hint'а.

Пример:

type
	TForm1 = class(TForm)
		procedure FormCreate(Sender: TObject);
	private
		{Private declarations}
	public
		procedure MyShowHint(var HintStr: string;
			var CanShow: Boolean;var HintInfo: THintInfo);
		{Public declarations}
end;

var
	Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.MyShowHint(var HintStr: string; var CanShow: Boolean;
								var HintInfo: THintInfo);
var
	i : integer;
begin
	for i := 0 to Application.ComponentCount - 1 do
	if Application.Components[i] is THintWindow then
		with THintWindow(Application.Components[i]).Canvas do
			begin
				Font.Name:= 'Arial';
				Font.Size:= 18;
				Font.Style:= [fsBold];
				HintInfo.HintColor:= clWhite;
			end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
	Application.OnShowHint := MyShowHint;
end;

Tags: ComponentCount, Components, fsBold, HintInfo, MyShowHint, procedure, THintInfo