diff --git a/components/tachart/languages/tachartstrconsts.de.po b/components/tachart/languages/tachartstrconsts.de.po
index ce488cc4ab..21c2d7fb97 100644
--- a/components/tachart/languages/tachartstrconsts.de.po
+++ b/components/tachart/languages/tachartstrconsts.de.po
@@ -471,6 +471,10 @@ msgstr "Diese %0:s-Instanz muss mindestens %1:d %2:s-Wert(e) pro Datenpunkt zur
 msgid "Editable chart source required"
 msgstr "Editierbare Chart-Datenquelle erforderlich"
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr "Stern (Linien)"
diff --git a/components/tachart/languages/tachartstrconsts.fi.po b/components/tachart/languages/tachartstrconsts.fi.po
index c479cf6c8d..63cb4ac1d1 100644
--- a/components/tachart/languages/tachartstrconsts.fi.po
+++ b/components/tachart/languages/tachartstrconsts.fi.po
@@ -459,6 +459,10 @@ msgstr ""
 msgid "Editable chart source required"
 msgstr ""
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr ""
diff --git a/components/tachart/languages/tachartstrconsts.fr.po b/components/tachart/languages/tachartstrconsts.fr.po
index 959c5eb7b2..cfb92b175e 100644
--- a/components/tachart/languages/tachartstrconsts.fr.po
+++ b/components/tachart/languages/tachartstrconsts.fr.po
@@ -469,6 +469,10 @@ msgstr ""
 msgid "Editable chart source required"
 msgstr ""
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr "Étoile (lignes)"
diff --git a/components/tachart/languages/tachartstrconsts.hu.po b/components/tachart/languages/tachartstrconsts.hu.po
index a19032b1e5..14dcf105c3 100644
--- a/components/tachart/languages/tachartstrconsts.hu.po
+++ b/components/tachart/languages/tachartstrconsts.hu.po
@@ -469,6 +469,10 @@ msgstr ""
 msgid "Editable chart source required"
 msgstr ""
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr "Csillag (vonalak)"
diff --git a/components/tachart/languages/tachartstrconsts.lt.po b/components/tachart/languages/tachartstrconsts.lt.po
index e2ecdd01bd..60ad2eebd3 100644
--- a/components/tachart/languages/tachartstrconsts.lt.po
+++ b/components/tachart/languages/tachartstrconsts.lt.po
@@ -470,6 +470,10 @@ msgstr ""
 msgid "Editable chart source required"
 msgstr ""
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr "Žvaigždės (linijos)"
diff --git a/components/tachart/languages/tachartstrconsts.pl.po b/components/tachart/languages/tachartstrconsts.pl.po
index a99924c84c..4a9b7f8352 100644
--- a/components/tachart/languages/tachartstrconsts.pl.po
+++ b/components/tachart/languages/tachartstrconsts.pl.po
@@ -468,6 +468,10 @@ msgstr ""
 msgid "Editable chart source required"
 msgstr ""
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr ""
diff --git a/components/tachart/languages/tachartstrconsts.pot b/components/tachart/languages/tachartstrconsts.pot
index b1ca782c26..00bb64345f 100644
--- a/components/tachart/languages/tachartstrconsts.pot
+++ b/components/tachart/languages/tachartstrconsts.pot
@@ -459,6 +459,10 @@ msgstr ""
 msgid "Editable chart source required"
 msgstr ""
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr ""
diff --git a/components/tachart/languages/tachartstrconsts.pt_BR.po b/components/tachart/languages/tachartstrconsts.pt_BR.po
index 75fb0b08b2..7f914a8977 100644
--- a/components/tachart/languages/tachartstrconsts.pt_BR.po
+++ b/components/tachart/languages/tachartstrconsts.pt_BR.po
@@ -469,6 +469,10 @@ msgstr "Esta instância %0:s deve ter ao menos %1:d %2:s valor(es) por ponto de
 msgid "Editable chart source required"
 msgstr "Fonte editável de gráfico requerida"
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr "Estrela (linhas)"
diff --git a/components/tachart/languages/tachartstrconsts.ru.po b/components/tachart/languages/tachartstrconsts.ru.po
index c3004f6300..a6a602c63f 100644
--- a/components/tachart/languages/tachartstrconsts.ru.po
+++ b/components/tachart/languages/tachartstrconsts.ru.po
@@ -469,6 +469,10 @@ msgstr "Этот экземпляр %0:s должен иметь не менее
 msgid "Editable chart source required"
 msgstr "Требуется доступный для редактирования источник данных для диаграммы"
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr "Звезда (из линий)"
diff --git a/components/tachart/languages/tachartstrconsts.se.po b/components/tachart/languages/tachartstrconsts.se.po
index 2192b0857d..8bda8d765f 100644
--- a/components/tachart/languages/tachartstrconsts.se.po
+++ b/components/tachart/languages/tachartstrconsts.se.po
@@ -472,6 +472,10 @@ msgstr ""
 msgid "Editable chart source required"
 msgstr ""
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr ""
diff --git a/components/tachart/languages/tachartstrconsts.uk.po b/components/tachart/languages/tachartstrconsts.uk.po
index 58fe8f5780..22eab8a3d6 100644
--- a/components/tachart/languages/tachartstrconsts.uk.po
+++ b/components/tachart/languages/tachartstrconsts.uk.po
@@ -472,6 +472,10 @@ msgstr "Цей примірник %0:s повинен мати принаймн
 msgid "Editable chart source required"
 msgstr "Потрібне джерело діаграми, доступне для редагування"
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr "Зірка (з ліній)"
diff --git a/components/tachart/languages/tachartstrconsts.zh_CN.po b/components/tachart/languages/tachartstrconsts.zh_CN.po
index 510d417ed2..1e826e2fca 100644
--- a/components/tachart/languages/tachartstrconsts.zh_CN.po
+++ b/components/tachart/languages/tachartstrconsts.zh_CN.po
@@ -470,6 +470,10 @@ msgstr ""
 msgid "Editable chart source required"
 msgstr ""
 
+#: tachartstrconsts.rssourcesorterror
+msgid "Selected sorting parameters are not supported by %s."
+msgstr ""
+
 #: tachartstrconsts.rsstarsymbol
 msgid "Star (lines)"
 msgstr "星(线)"
diff --git a/components/tachart/tachartstrconsts.pas b/components/tachart/tachartstrconsts.pas
index 3830aa8192..b7f00a14a1 100644
--- a/components/tachart/tachartstrconsts.pas
+++ b/components/tachart/tachartstrconsts.pas
@@ -78,12 +78,12 @@ resourcestring
   rsSourceNotEditable = 'Editable chart source required';
   rsSourceCountError = '%0:s requires a chart source with at least %1:d %2:s value(s) per data point.';
   rsSourceCountError2 = 'This %0:s instance must have at least %1:d %2:s value(s) per data point.';
+  rsSourceSortError = 'Selected sorting parameters are not supported by %s.';
   rsListSourceStringFormatError = 'The data value count in the %0:s.DataPoints '+
     'string "%1:s" differs from what is expected from XCount and YCount.';
   rsListSourceNumericError = 'The %0:s.DataPoints string "%1:s" is not a valid number.';
   rsListSourceColorError = 'The %0:s.DataPoints string "%1:s" is not an integer.';
 
-
   // Transformations
   tasAxisTransformsEditorTitle = 'Edit axis transformations';
   rsAutoScale = 'Auto scale';
diff --git a/components/tachart/tacustomseries.pas b/components/tachart/tacustomseries.pas
index 5fee42055e..62ec0db62c 100644
--- a/components/tachart/tacustomseries.pas
+++ b/components/tachart/tacustomseries.pas
@@ -1940,15 +1940,15 @@ begin
   {FLoBound and FUpBound fields may be outdated here (if axis' range has been
    changed after the last series' painting). FLoBound and FUpBound will be fully
    updated later, in a PrepareGraphPoints() call. But we need them now. If data
-   source is sorted, obtaining FLoBound and FUpBound is very fast (binary search) -
-   so we call FindExtentInterval() with True as the second parameter. If data
-   source is not sorted, obtaining FLoBound and FUpBound requires enumerating all
-   the data points to see, if they are in the current chart's viewport. But this
-   is exactly what we are going to do in the loop below, so obtaining true FLoBound
-   and FUpBound values makes no sense in this case - so we call FindExtentInterval()
-   with False as the second parameter, thus setting FLoBound to 0 and FUpBound to
-   Count-1}
-  FindExtentInterval(ParentChart.CurrentExtent, Source.IsSorted);
+   source is sorted by X in the ascending order, obtaining FLoBound and FUpBound
+   is very fast (binary search) - so we call FindExtentInterval() with True as
+   the second parameter. Otherwise, obtaining FLoBound and FUpBound requires
+   enumerating all the data points to see, if they are in the current chart's
+   viewport. But this is exactly what we are going to do in the loop below, so
+   obtaining true FLoBound and FUpBound values makes no sense in this case - so
+   we call FindExtentInterval() with False as the second parameter, thus setting
+   FLoBound to 0 and FUpBound to Count-1}
+  FindExtentInterval(ParentChart.CurrentExtent, Source.IsSortedByXAsc);
 
   with Extent do
     center := AxisToGraphY((a.y + b.y) * 0.5);
diff --git a/components/tachart/tacustomsource.pas b/components/tachart/tacustomsource.pas
index 210e80e2b7..a5b2bb90fc 100644
--- a/components/tachart/tacustomsource.pas
+++ b/components/tachart/tacustomsource.pas
@@ -71,9 +71,10 @@ type
 type
   EBufferError = class(EChartError);
   EEditableSourceRequired = class(EChartError);
+  EListSourceStringError = class(EChartError);
+  ESortError = class(EChartError);
   EXCountError = class(EChartError);
   EYCountError = class(EChartError);
-  EListSourceStringError = class(EChartError);
 
   TChartValueText = record
     FText: String;
@@ -175,9 +176,11 @@ type
     property IndexPlus: Integer index 0 read GetIndex write SetIndex default -1;
     property ValueMinus: Double index 1 read GetValue write SetValue stored IsErrorBarValueStored;
     property ValuePlus: Double index 0 read GetValue write SetValue stored IsErrorBarValueStored;
-
   end;
 
+  TChartSortBy = (sbX, sbY, sbColor, sbText, sbCustom);
+  TChartSortDir = (sdAscending, sdDescending);
+
   TCustomChartSource = class(TBasicChartSource)
   strict private
     FErrorBarData: array[0..1] of TChartErrorBarData;
@@ -197,6 +200,9 @@ type
     FYListExtentIsValid: Boolean;
     FValuesTotal: Double;
     FValuesTotalIsValid: Boolean;
+    FSortBy: TChartSortBy;
+    FSortDir: TChartSortDir;
+    FSortIndex: Cardinal;
     FXCount: Cardinal;
     FYCount: Cardinal;
     function CalcExtentXYList(UseXList: Boolean): TDoubleRect;
@@ -207,12 +213,19 @@ type
     function GetHasErrorBars(Which: Integer): Boolean;
     function GetItem(AIndex: Integer): PChartDataItem; virtual; abstract;
     procedure InvalidateCaches;
+    procedure SetSortBy(AValue: TChartSortBy); virtual;
+    procedure SetSortDir(AValue: TChartSortDir); virtual;
+    procedure SetSortIndex(AValue: Cardinal); virtual;
     procedure SetXCount(AValue: Cardinal); virtual; abstract;
     procedure SetYCount(AValue: Cardinal); virtual; abstract;
     property XErrorBarData: TChartErrorBarData index 0 read GetErrorBarData
       write SetErrorBarData stored IsErrorBarDataStored;
     property YErrorBarData: TChartErrorBarData index 1 read GetErrorBarData
       write SetErrorBarData stored IsErrorBarDataStored;
+  protected
+    property SortBy: TChartSortBy read FSortBy write SetSortBy default sbX;
+    property SortDir: TChartSortDir read FSortDir write SetSortDir default sdAscending;
+    property SortIndex: Cardinal read FSortIndex write SetSortIndex default 0;
   public
     constructor Create(AOwner: TComponent); override;
     destructor Destroy; override;
@@ -247,6 +260,7 @@ type
     function IsXErrorIndex(AXIndex: Integer): Boolean;
     function IsYErrorIndex(AYIndex: Integer): Boolean;
     function IsSorted: Boolean; virtual;
+    function IsSortedByXAsc: Boolean;
     procedure ValuesInRange(
       AParams: TValuesInRangeParams; var AValues: TChartValueTextArray); virtual;
     function ValuesTotal: Double; virtual;
@@ -288,7 +302,7 @@ procedure SetDataItemDefaults(var AItem: TChartDataItem);
 implementation
 
 uses
-  Math, StrUtils, SysUtils, TAMath;
+  Math, StrUtils, SysUtils, TAMath, TAChartStrConsts;
 
 function CompareChartValueTextPtr(AItem1, AItem2: Pointer): Integer;
 begin
@@ -895,8 +909,6 @@ begin
   end;
 end;
 
-
-
 class procedure TCustomChartSource.CheckFormat(const AFormat: String);
 begin
   Format(AFormat, [0.0, 0.0, '', 0.0, 0.0]);
@@ -907,6 +919,9 @@ var
   i: Integer;
 begin
   inherited Create(AOwner);
+  FSortBy := sbX;
+  FSortDir := sdAscending;
+  FSortIndex := 0;
   FXCount := 1;
   FYCount := 1;
   for i:=Low(FErrorBarData) to High(FErrorBarData) do begin
@@ -1011,7 +1026,8 @@ end;
 
 // ALB -> leftmost item where X >= AXMin, or Count if no such item
 // ALB -> rightmost item where X <= AXMax, or -1 if no such item
-// If the source is sorted, performs binary search. Otherwise, skips NaNs.
+// If the source is sorted by X in the ascending order, performs
+// binary search. Otherwise, skips NaNs.
 procedure TCustomChartSource.FindBounds(
   AXMin, AXMax: Double; out ALB, AUB: Integer);
 
@@ -1041,7 +1057,7 @@ procedure TCustomChartSource.FindBounds(
 
 begin
   EnsureOrder(AXMin, AXMax);
-  if IsSorted then begin
+  if IsSortedByXAsc then begin
     ALB := FindLB(AXMin, 0, Count - 1);
     AUB := FindUB(AXMax, 0, Count - 1);
   end
@@ -1250,6 +1266,16 @@ begin
     Result := (FIndex[AIndex] <> -1) or (FValue[AIndex] <> -1) or (FKind <> ebkNone);
 end;
 
+function TCustomChartSource.IsSorted: Boolean; inline;
+begin
+  Result := false;
+end;
+
+function TCustomChartSource.IsSortedByXAsc: Boolean;
+begin
+  Result := IsSorted and (FSortBy = sbX) and (FSortDir = sdAscending) and (FSortIndex = 0);
+end;
+
 function TCustomChartSource.IsXErrorIndex(AXIndex: Integer): Boolean;
 begin
   Result :=
@@ -1267,11 +1293,6 @@ begin
     (AYIndex > -1);
 end;
 
-function TCustomChartSource.IsSorted: Boolean;
-begin
-  Result := false;
-end;
-
 procedure TCustomChartSource.SetErrorBarData(AIndex: Integer;
   AValue: TChartErrorBarData);
 begin
@@ -1279,6 +1300,24 @@ begin
   Notify;
 end;
 
+procedure TCustomChartSource.SetSortBy(AValue: TChartSortBy);
+begin
+  if FSortBy <> AValue then
+    raise ESortError.CreateFmt(rsSourceSortError, [ClassName]);
+end;
+
+procedure TCustomChartSource.SetSortDir(AValue: TChartSortDir);
+begin
+  if FSortDir <> AValue then
+    raise ESortError.CreateFmt(rsSourceSortError, [ClassName]);
+end;
+
+procedure TCustomChartSource.SetSortIndex(AValue: Cardinal);
+begin
+  if FSortIndex <> AValue then
+    raise ESortError.CreateFmt(rsSourceSortError, [ClassName]);
+end;
+
 procedure TCustomChartSource.SortValuesInRange(
   var AValues: TChartValueTextArray; AStart, AEnd: Integer);
 var
@@ -1421,7 +1460,7 @@ begin
     cnt += 1;
   end;
 
-  if not IsSorted and not IsValueTextsSorted(AValues, start, cnt - 1) then begin
+  if not IsSortedByXAsc and not IsValueTextsSorted(AValues, start, cnt - 1) then begin
     SortValuesInRange(AValues, start, cnt - 1);
     if aipUseMinLength in AParams.FIntervals.Options then
       cnt := EnsureMinLength(start, cnt - 1);
diff --git a/components/tachart/tamultiseries.pas b/components/tachart/tamultiseries.pas
index eb32a9287f..b74b9ebcfb 100644
--- a/components/tachart/tamultiseries.pas
+++ b/components/tachart/tamultiseries.pas
@@ -879,7 +879,7 @@ begin
   if Count = 0 then exit;
   if not RequestValidChartScaling then exit;
 
-  FindExtentInterval(ParentChart.CurrentExtent, Source.IsSorted);
+  FindExtentInterval(ParentChart.CurrentExtent, Source.IsSortedByXAsc);
   with Extent do
     center := AxisToGraphY((a.y + b.y) * 0.5);
   UpdateLabelDirectionReferenceLevel(0, 0, center);
diff --git a/components/tachart/tasources.pas b/components/tachart/tasources.pas
index 32a6200c5e..dcd696c502 100644
--- a/components/tachart/tasources.pas
+++ b/components/tachart/tasources.pas
@@ -19,13 +19,33 @@ uses
   Classes, Types, TAChartUtils, TACustomSource;
 
 type
-  { TListChartSource }
+  TChartSortCompare = function(AItem1, AItem2: Pointer): Integer of object;
 
-  TListChartSource = class(TCustomChartSource)
+  { TCustomSortedChartSource }
+
+  TCustomSortedChartSource = class(TCustomChartSource)
   private
+    FOnCompare: TChartSortCompare;
+    procedure SetSorted(AValue: Boolean);
+  protected
     FData: TFPList;
-    FDataPoints: TStrings;
     FSorted: Boolean;
+    function DefaultCompare(AItem1, AItem2: Pointer): Integer; virtual; abstract;
+    procedure ExecSort(ACompare: TChartSortCompare); virtual;
+    procedure SetSortBy(AValue: TChartSortBy); override;
+    procedure SetSortDir(AValue: TChartSortDir); override;
+    procedure SetSortIndex(AValue: Cardinal); override;
+    property Sorted: Boolean read FSorted write SetSorted default false;
+    property OnCompare: TChartSortCompare read FOnCompare write FOnCompare;
+  public
+    function IsSorted: Boolean; override;
+    procedure Sort;
+  end;
+
+  { TListChartSource }
+  TListChartSource = class(TCustomSortedChartSource)
+  private
+    FDataPoints: TStrings;
     FXCountMin: Cardinal;
     FYCountMin: Cardinal;
     procedure AddAt(
@@ -33,9 +53,9 @@ type
     procedure ClearCaches;
     function NewItem: PChartDataItem;
     procedure SetDataPoints(AValue: TStrings);
-    procedure SetSorted(AValue: Boolean);
     procedure UpdateCachesAfterAdd(AX, AY: Double);
   protected
+    function DefaultCompare(AItem1, AItem2: Pointer): Integer; override;
     function GetCount: Integer; override;
     function GetItem(AIndex: Integer): PChartDataItem; override;
     procedure Loaded; override;
@@ -61,23 +81,24 @@ type
     procedure Clear;
     procedure CopyFrom(ASource: TCustomChartSource);
     procedure Delete(AIndex: Integer);
-    function IsSorted: Boolean; override;
-
     procedure SetColor(AIndex: Integer; AColor: TChartColor);
     procedure SetText(AIndex: Integer; AValue: String);
     function SetXValue(AIndex: Integer; AValue: Double): Integer;
     procedure SetXList(AIndex: Integer; const AXList: array of Double);
     procedure SetYList(AIndex: Integer; const AYList: array of Double);
     procedure SetYValue(AIndex: Integer; AValue: Double);
-
-    procedure Sort;
   published
     property DataPoints: TStrings read FDataPoints write SetDataPoints;
-    property Sorted: Boolean read FSorted write SetSorted default false;
     property XCount;
     property XErrorBarData;
     property YCount;
     property YErrorBarData;
+    // Sorting
+    property SortBy;
+    property SortDir;
+    property Sorted;
+    property SortIndex;
+    property OnCompare;
   end;
 
   { TMWCRandomGenerator }
@@ -203,6 +224,7 @@ type
     FOriginYCount: Cardinal;
     FPercentage: Boolean;
     FReorderYList: String;
+    FSorted: Boolean;
     FYOrder: array of Integer;
 
     procedure CalcAccumulation(AIndex: Integer);
@@ -228,7 +250,6 @@ type
   public
     constructor Create(AOwner: TComponent); override;
     destructor Destroy; override;
-
     function IsSorted: Boolean; override;
   published
     property AccumulationDirection: TChartAccumulationDirection
@@ -253,6 +274,7 @@ uses
   Math, StrUtils, SysUtils, TAMath, TAChartStrConsts;
 
 type
+  TCustomChartSourceAccess = class(TCustomChartSource);
 
   { TListChartSourceStrings }
 
@@ -276,6 +298,18 @@ type
     procedure Insert(Index: Integer; const S: String); override;
   end;
 
+function CompareFloat(x1, x2: Double): Integer;
+begin
+  if IsNaN(x1) and IsNaN(x2) then
+    Result := 0
+  else if IsNaN(x1) then
+    Result := +1
+  else if IsNaN(x2) then
+    Result := -1
+  else
+    Result := CompareValue(x1, x2);
+end;
+
 procedure Register;
 begin
   RegisterComponents(
@@ -285,6 +319,7 @@ begin
     ]);
 end;
 
+
 { TListChartSourceStrings }
 
 procedure TListChartSourceStrings.Clear;
@@ -484,13 +519,106 @@ begin
     end;
 end;
 
+
+{ TCustomSortedChartSource }
+
+{ Built-in sorting algorithm of the ChartSource, a standard QuickSort.
+  Copied from the classes unit because the compare function must be a method. }
+procedure TCustomSortedChartSource.ExecSort(ACompare: TChartSortCompare);
+
+  procedure QuickSort(L, R: Longint);
+  var
+    I, J : Longint;
+    P, Q : Pointer;
+  begin
+   repeat
+     I := L;
+     J := R;
+     P := FData[(L + R) div 2];
+     repeat
+       while ACompare(P, FData[i]) > 0 do
+         I := I + 1;
+       while ACompare(P, FData[J]) < 0 do
+         J := J - 1;
+       If I <= J then
+       begin
+         Q := FData[I];
+         FData[I] := FData[J];
+         FData[J] := Q;
+         I := I + 1;
+         J := J - 1;
+       end;
+     until I > J;
+     if J - L < R - I then
+     begin
+       if L < J then
+         QuickSort(L, J);
+       L := I;
+     end
+     else
+     begin
+       if I < R then
+         QuickSort(I, R);
+       R := J;
+     end;
+   until L >= R;
+  end;
+
+begin
+  if FData.Count < 2 then exit;
+  QuickSort(0, FData.Count-1);
+end;
+
+function TCustomSortedChartSource.IsSorted: Boolean; inline;
+begin
+  Result := FSorted;
+end;
+
+procedure TCustomSortedChartSource.SetSortBy(AValue: TChartSortBy);
+begin
+  if FSortBy = AValue then exit;
+  FSortBy := AValue;
+  Sort;
+end;
+
+procedure TCustomSortedChartSource.SetSorted(AValue: Boolean);
+begin
+  if FSorted = AValue then exit;
+  FSorted := AValue;
+  Sort;
+end;
+
+procedure TCustomSortedChartSource.SetSortDir(AValue: TChartSortDir);
+begin
+  if FSortDir = AValue then exit;
+  FSortDir := AValue;
+  Sort;
+end;
+
+procedure TCustomSortedChartSource.SetSortIndex(AValue: Cardinal);
+begin
+  if FSortIndex = AValue then exit;
+  FSortIndex := AValue;
+  Sort;
+end;
+
+procedure TCustomSortedChartSource.Sort;
+begin
+  if (FSortBy = sbCustom) then begin
+    if Assigned(FOnCompare) then ExecSort(FOnCompare);
+  end else
+    ExecSort(@DefaultCompare);
+  Notify;
+end;
+
+
 { TListChartSource }
 
 function TListChartSource.Add(
   AX, AY: Double; const ALabel: String; AColor: TChartColor): Integer;
 begin
   Result := FData.Count;
-  if Sorted then
+  if IsSortedByXAsc then
     // Keep data points ordered by X coordinate.
     // Note that this leads to O(N^2) time except
     // for the case of adding already ordered points.
@@ -603,7 +731,17 @@ begin
         SetXList(FData.Count - 1, XList);
         SetYList(FData.Count - 1, YList);
       end;
-    if Sorted and not ASource.IsSorted then Sort;
+
+    if IsSorted then begin
+      if ASource.IsSorted and
+        (SortBy = TCustomChartSourceAccess(ASource).SortBy) and
+        (SortDir = TCustomChartSourceAccess(ASource).SortDir) and
+        (SortIndex = TCustomChartSourceAccess(ASource).SortIndex) and
+        (SortBy <> sbCustom)
+      then
+        exit;
+      Sort;
+    end;
   finally
     EndUpdate;
   end;
@@ -628,6 +766,21 @@ begin
     FYCount := FYCountMin;
 end;
 
+function TListChartSource.DefaultCompare(AItem1, AItem2: Pointer): Integer;
+var
+  item1: PChartDataItem absolute AItem1;
+  item2: PChartDataItem absolute AItem2;
+begin
+ case FSortBy of
+   sbX: Result := CompareFloat(item1^.GetX(FSortIndex), item2^.GetX(FSortIndex));
+   sbY: Result := CompareFloat(item1^.GetY(FSortIndex), item2^.GetY(FSortIndex));
+   sbColor: Result := CompareValue(item1^.Color, item2^.Color);
+   sbText: Result := CompareText(item1^.Text, item2^.Text);
+   sbCustom: Result := FOnCompare(AItem1, AItem2);
+ end;
+ if FSortDir = sdDescending then Result := -Result;
+end;
+
 procedure TListChartSource.Delete(AIndex: Integer);
 begin
   // Optimization
@@ -670,11 +823,6 @@ begin
   Result := PChartDataItem(FData.Items[AIndex]);
 end;
 
-function TListChartSource.IsSorted: Boolean;
-begin
-  Result := Sorted;
-end;
-
 function TListChartSource.NewItem: PChartDataItem;
 begin
   New(Result);
@@ -697,19 +845,12 @@ begin
   BeginUpdate;
   try
     FDataPoints.Assign(AValue);
-    if Sorted then Sort;
+    if IsSorted then Sort;
   finally
     EndUpdate;
   end;
 end;
 
-procedure TListChartSource.SetSorted(AValue: Boolean);
-begin
-  if FSorted = AValue then exit;
-  FSorted := AValue;
-  if Sorted then Sort;
-end;
-
 procedure TListChartSource.SetText(AIndex: Integer; AValue: String);
 begin
   with Item[AIndex]^ do begin
@@ -766,7 +907,7 @@ var
   end;
 
 begin
-  if Sorted then
+  if IsSortedByXAsc then
     if IsNan(AValue) then
       raise EChartError.CreateFmt('X = NaN in sorted source %s', [NameOrClassName(Self)]);
   oldX := Item[AIndex]^.X;
@@ -774,7 +915,7 @@ begin
   if IsEquivalent(oldX, AValue) then exit;
   Item[AIndex]^.X := AValue;
   UpdateExtent;
-  if Sorted then begin
+  if IsSortedByXAsc then begin
     if AValue > oldX then
       while (Result < Count - 1) and (Item[Result + 1]^.X < AValue) do
         Inc(Result)
@@ -844,32 +985,6 @@ begin
   Notify;
 end;
 
-function CompareFloat(x1, x2: Double): Integer;
-begin
-  if IsNaN(x1) and IsNaN(x2) then
-    Result := 0
-  else if IsNaN(x1) then
-    Result := +1
-  else if IsNaN(x2) then
-    Result := -1
-  else
-    Result := CompareValue(x1, x2);
-end;
-
-function CompareDataItemX(AItem1, AItem2: Pointer): Integer;
-var
-  item1: PChartDataItem absolute AItem1;
-  item2: PChartDataItem absolute AItem2;
-begin
-  Result := CompareFloat(item1^.X, item2^.X);
-end;
-
-procedure TListChartSource.Sort;
-begin
-  FData.Sort(@CompareDataItemX);
-  Notify;
-end;
-
 procedure TListChartSource.UpdateCachesAfterAdd(AX, AY: Double);
 begin
   if IsUpdating then exit; // Optimization
@@ -1035,7 +1150,7 @@ begin
   Result := @FCurItem;
 end;
 
-function TRandomChartSource.IsSorted: Boolean;
+function TRandomChartSource.IsSorted: Boolean; inline;
 begin
   Result := not RandomX;
 end;
@@ -1142,9 +1257,9 @@ begin
   Result := @FItem;
 end;
 
-function TUserDefinedChartSource.IsSorted: Boolean;
+function TUserDefinedChartSource.IsSorted: Boolean; inline;
 begin
-  Result := Sorted;
+  Result := FSorted;
 end;
 
 procedure TUserDefinedChartSource.Reset;
@@ -1350,6 +1465,22 @@ end;
 
 procedure TCalculatedChartSource.Changed(ASender: TObject);
 begin
+  if FOrigin <> nil then begin
+    FSortBy := TCustomChartSourceAccess(Origin).SortBy;
+    FSortDir := TCustomChartSourceAccess(Origin).SortDir;
+    FSortIndex := TCustomChartSourceAccess(Origin).SortIndex;
+    // We recalculate Y values, so we can't guarantee, that transformed
+    // data is still sorted by Y or by Origin's custom algorithm
+    FSorted := (FSortBy in [sbX, sbColor, sbText]) and Origin.IsSorted;
+    FXCount := Origin.XCount;
+  end else begin
+    FSortBy := sbX;
+    FSortDir := sdAscending;
+    FSortIndex := 0;
+    FSorted := false;
+    FXCount := 0;
+  end;
+
   if
     (FOrigin <> nil) and (ASender = FOrigin) and
     (FOrigin.YCount <> FOriginYCount)
@@ -1437,10 +1568,7 @@ end;
 
 function TCalculatedChartSource.IsSorted: Boolean;
 begin
-  if Origin <> nil then
-    Result := Origin.IsSorted
-  else
-    Result := false;
+  Result := FSorted;
 end;
 
 procedure TCalculatedChartSource.RangeAround(