Error occurred with TRealativePanel

VCL TMS VCL UI Pack
1
Windows 10, Delphi 10.1 Update2.

Hello.

When the TAdvStringGrid has a parent that is TRelativePanel, the pannel occurred AV error during initialize. The method is TCustomRelativePanel.AlignControls.
But the TStrinGrid or the other common component does not.

Please check this issue for me. Thank you.
The code like a followings:

object Form25: TForm25
  Left = 0
  Top = 0
  Caption = 'Form25'
  ClientHeight = 397
  ClientWidth = 707
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object RelativePanel1: TRelativePanel
    Left = 0
    Top = 0
    Width = 707
    Height = 397
    ControlCollection = <
      item
        Control = AdvStringGrid1
        AlignBottomWithPanel = False
        AlignHorizontalCenterWithPanel = True
        AlignLeftWithPanel = False
        AlignRightWithPanel = False
        AlignTopWithPanel = False
        AlignVerticalCenterWithPanel = True
      end>
    Align = alClient
    TabOrder = 0
    ExplicitLeft = 272
    ExplicitTop = 200
    ExplicitWidth = 185
    ExplicitHeight = 41
    DesignSize = (
      707
      397)
    object AdvStringGrid1: TAdvStringGrid
      Left = 152
      Top = 72
      Width = 400
      Height = 250
      Cursor = crDefault
      Anchors = []
      DrawingStyle = gdsClassic
      Font.Charset = DEFAULT_CHARSET
      Font.Color = clWindowText
      Font.Height = -11
      Font.Name = 'Tahoma'
      Font.Style = []
      ParentFont = False
      ScrollBars = ssBoth
      TabOrder = 0
      HoverRowCells = [hcNormal, hcSelected]
      ActiveCellFont.Charset = DEFAULT_CHARSET
      ActiveCellFont.Color = clWindowText
      ActiveCellFont.Height = -11
      ActiveCellFont.Name = 'Tahoma'
      ActiveCellFont.Style = [fsBold]
      ControlLook.FixedGradientHoverFrom = clGray
      ControlLook.FixedGradientHoverTo = clWhite
      ControlLook.FixedGradientDownFrom = clGray
      ControlLook.FixedGradientDownTo = clSilver
      ControlLook.DropDownHeader.Font.Charset = DEFAULT_CHARSET
      ControlLook.DropDownHeader.Font.Color = clWindowText
      ControlLook.DropDownHeader.Font.Height = -11
      ControlLook.DropDownHeader.Font.Name = 'Tahoma'
      ControlLook.DropDownHeader.Font.Style = []
      ControlLook.DropDownHeader.Visible = True
      ControlLook.DropDownHeader.Buttons = <>
      ControlLook.DropDownFooter.Font.Charset = DEFAULT_CHARSET
      ControlLook.DropDownFooter.Font.Color = clWindowText
      ControlLook.DropDownFooter.Font.Height = -11
      ControlLook.DropDownFooter.Font.Name = 'Tahoma'
      ControlLook.DropDownFooter.Font.Style = []
      ControlLook.DropDownFooter.Visible = True
      ControlLook.DropDownFooter.Buttons = <>
      Filter = <>
      FilterDropDown.Font.Charset = DEFAULT_CHARSET
      FilterDropDown.Font.Color = clWindowText
      FilterDropDown.Font.Height = -11
      FilterDropDown.Font.Name = 'Tahoma'
      FilterDropDown.Font.Style = []
      FilterDropDown.TextChecked = 'Checked'
      FilterDropDown.TextUnChecked = 'Unchecked'
      FilterDropDownClear = '(All)'
      FilterEdit.TypeNames.Strings = (
        'Starts with'
        'Ends with'
        'Contains'
        'Not contains'
        'Equal'
        'Not equal'
        'Larger than'
        'Smaller than'
        'Clear')
      FixedRowHeight = 22
      FixedFont.Charset = DEFAULT_CHARSET
      FixedFont.Color = clWindowText
      FixedFont.Height = -11
      FixedFont.Name = 'Tahoma'
      FixedFont.Style = [fsBold]
      FloatFormat = '%.2f'
      HoverButtons.Buttons = <>
      HoverButtons.Position = hbLeftFromColumnLeft
      HTMLSettings.ImageFolder = 'images'
      HTMLSettings.ImageBaseName = 'img'
      PrintSettings.DateFormat = 'dd/mm/yyyy'
      PrintSettings.Font.Charset = DEFAULT_CHARSET
      PrintSettings.Font.Color = clWindowText
      PrintSettings.Font.Height = -11
      PrintSettings.Font.Name = 'Tahoma'
      PrintSettings.Font.Style = []
      PrintSettings.FixedFont.Charset = DEFAULT_CHARSET
      PrintSettings.FixedFont.Color = clWindowText
      PrintSettings.FixedFont.Height = -11
      PrintSettings.FixedFont.Name = 'Tahoma'
      PrintSettings.FixedFont.Style = []
      PrintSettings.HeaderFont.Charset = DEFAULT_CHARSET
      PrintSettings.HeaderFont.Color = clWindowText
      PrintSettings.HeaderFont.Height = -11
      PrintSettings.HeaderFont.Name = 'Tahoma'
      PrintSettings.HeaderFont.Style = []
      PrintSettings.FooterFont.Charset = DEFAULT_CHARSET
      PrintSettings.FooterFont.Color = clWindowText
      PrintSettings.FooterFont.Height = -11
      PrintSettings.FooterFont.Name = 'Tahoma'
      PrintSettings.FooterFont.Style = []
      PrintSettings.PageNumSep = '/'
      SearchFooter.FindNextCaption = 'Find &next'
      SearchFooter.FindPrevCaption = 'Find &previous'
      SearchFooter.Font.Charset = DEFAULT_CHARSET
      SearchFooter.Font.Color = clWindowText
      SearchFooter.Font.Height = -11
      SearchFooter.Font.Name = 'Tahoma'
      SearchFooter.Font.Style = []
      SearchFooter.HighLightCaption = 'Highlight'
      SearchFooter.HintClose = 'Close'
      SearchFooter.HintFindNext = 'Find next occurrence'
      SearchFooter.HintFindPrev = 'Find previous occurrence'
      SearchFooter.HintHighlight = 'Highlight occurrences'
      SearchFooter.MatchCaseCaption = 'Match case'
      SearchFooter.ResultFormat = '(%d of %d)'
      SortSettings.DefaultFormat = ssAutomatic
      Version = '8.2.4.0'
    end
  end
end
2

We could reproduce this but we have unfortunately not yet found a solution or workaround for now, as it appears to be a strange & tricky problem.

3
Hello Bruno Fierens.
To avoid this issue, I uses simple trick that change the parent at a runtime. 

And I am hope that solved this issue.

Best regards
JH Jang.

procedure TForm36.FormCreate(Sender: TObject);
begin
  Grid.Parent := PanelMain;
...
end;
4

We've also seen that this issue does not happen on Delphi 10.2 Tokyo, so apparently, Embarcadero also did changes in TRelativePanel. We'll need to deeper investigate these changes.