Enhancement: Paint a splitter frame in TSpTBXCustomSplitter.

[pyscripter]

The SpTBXSplitter looks better with frame painted. In my fork I use a function:

procedure PaintSplitterFrame(Canvas : TCanvas; IsVertical: Boolean; var R: TRect);
var
  FrameBrush: HBRUSH;
begin
  if IsVertical then
    InflateRect(R, -1, 2)
  else
    InflateRect(R, 2, -1);
  OffsetRect(R, 1, 1);
  FrameBrush := CreateSolidBrush(ColorToRGB(CurrentSkin.GetThemedSystemColor(clBtnHighlight)));
  FrameRect(Canvas.Handle, R, FrameBrush);
  DeleteObject(FrameBrush);
  OffsetRect(R, -2, -2);
  FrameBrush := CreateSolidBrush(ColorToRGB(CurrentSkin.GetThemedSystemColor(clBtnShadow)));
  FrameRect(Canvas.Handle, R, FrameBrush);
  DeleteObject(FrameBrush);
end;

and in TSpTBXCustomSplitter.Paint added one line:

procedure TSpTBXCustomSplitter.Paint;
var
  ClientR, R, DragHandleR: TRect;
  C1, C2: TColor;
  PaintDefault: Boolean;
begin
  ClientR := ClientRect;
  PaintDefault := True;
  DoDrawBackground(Canvas, ClientR, pstPrePaint, PaintDefault);
  if PaintDefault then begin
    // Paint background
    if SkinManager.GetSkinType = sknSkin then
      CurrentSkin.PaintBackground(Canvas, ClientR, skncSplitter, sknsNormal, True, False, IsVertical)
    else begin
      if Color = clNone then
        Canvas.Brush.Color := CurrentSkin.GetThemedSystemColor(clBtnFace)
      else
        Canvas.Brush.Color := Color;
      SpFillRect(Canvas, ClientR, Canvas.Brush.Color);
      PaintSplitterFrame(Canvas, IsVertical, ClientR);  //<-- added
    end;

Alternatively, there could be an option for framing the splitter.