Allow assigning custom THintWindowClass

[IgitBuh]

VTV doesn't use the application's HintWindowClass, so if a custom one has been assigned (as easy as HintWindowClass := TMyHintWindow;) it's used for all components except for VTV.
Unfortunately, there's no direct way to use a custom hint style, so in order to assign it, one has either to inherit or intercept TVirtualStringTree.

I'm currently doing this:

type
  TVirtualStringTree = class(VirtualTrees.TVirtualStringTree)
  public
    function GetHintWindowClass: THintWindowClass; override;
  end;

function TVirtualStringTree.GetHintWindowClass: THintWindowClass;
begin
  Result := TMyHintWindow;
end;

It works, but I feel like this shouldn't be necessary.

Would it please be possible to have a public property like "HintWindowClass" to easily assign a custom THintWindowClass?
Alternatively or additionally, there could be an option to automatically use the THintWindowClass of the application, like toUseApplicationHintWindowClass.

[joachimmarder]

It works, but I feel like this shouldn't be necessary.

Agreed. I noticed that too a while ago and started digging why VTV needs it own hint window class at all. One outcome was #730.

[joachimmarder]

We should remove TVTHintData.DefaultHint and determine TVTHintData.HintText in TBaseVirtualTree.CMHintShow() and not in TVirtualTreeHintWindow.CalcHintRect(). We should aim that the default VCL THintWindow is working, at least header hints are not shown here.