Create project with a unit containing the DFM at the end of this post.
Run with 10.1.7.0, the fixed cell with be grey with and the selected cell blue.
Install 10.2.0.0, open, save, close and reopen the unit, the fixed cell with be blue with and the selected cell organge. (The DFM will automatically gain UIStyle = tsOffice2003Blue)
Try to fix it by changing Look to Standard and then back to Windows XP. Save, close and reopen the unit and will be blue and orange again.
object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 300
  ClientWidth = 635
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object grille: TAdvStringGrid
    Left = 0
    Top = 30
    Width = 769
    Height = 221
    Cursor = crDefault
    Align = alClient
    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 = '8.5.1.0'
  end
end