diff --git a/components/tachart/demo/axis/main.lfm b/components/tachart/demo/axis/main.lfm
index 68f3a40b35..e323aa8819 100644
--- a/components/tachart/demo/axis/main.lfm
+++ b/components/tachart/demo/axis/main.lfm
@@ -8,24 +8,24 @@ object Form1: TForm1
   ClientWidth = 533
   OnCreate = FormCreate
   Position = poScreenCenter
-  LCLVersion = '1.1'
+  LCLVersion = '1.7'
   object PageControl1: TPageControl
     Left = 0
     Height = 430
     Top = 0
     Width = 533
-    ActivePage = tsCustomMarks
+    ActivePage = tsDateTime
     Align = alClient
-    TabIndex = 0
+    TabIndex = 3
     TabOrder = 0
     Options = [nboKeyboardTabSwitch]
     object tsCustomMarks: TTabSheet
       Caption = 'Customized marks'
-      ClientHeight = 404
+      ClientHeight = 402
       ClientWidth = 525
       object ChartCustomMarks: TChart
         Left = 0
-        Height = 404
+        Height = 402
         Top = 0
         Width = 525
         AxisList = <        
@@ -78,7 +78,6 @@ object Form1: TForm1
           'TAChart'
         )
         Align = alClient
-        ParentColor = False
         object ChartCustomMarksBarSeries1: TBarSeries
           Marks.Frame.Visible = False
           Marks.LabelBrush.Style = bsClear
@@ -118,7 +117,6 @@ object Form1: TForm1
           'TAChart'
         )
         Align = alClient
-        ParentColor = False
       end
     end
     object tsSubmarks: TTabSheet
@@ -177,7 +175,6 @@ object Form1: TForm1
           'TAChart'
         )
         Align = alClient
-        ParentColor = False
         object ChartSubmarksLineSeries1: TLineSeries
           Source = udcsGraph
         end
@@ -185,11 +182,11 @@ object Form1: TForm1
     end
     object tsDateTime: TTabSheet
       Caption = 'Date and time'
-      ClientHeight = 404
+      ClientHeight = 402
       ClientWidth = 525
       object ChartDateTime: TChart
         Left = 0
-        Height = 404
+        Height = 368
         Top = 0
         Width = 525
         AxisList = <        
@@ -216,11 +213,32 @@ object Form1: TForm1
         Title.Visible = True
         Toolset = ChartToolsetDateTime
         Align = alClient
-        ParentColor = False
         object ChartDateTimeLineSeries1: TLineSeries
           Source = rcsDates
         end
       end
+      object Panel1: TPanel
+        Left = 0
+        Height = 34
+        Top = 368
+        Width = 525
+        Align = alBottom
+        BevelOuter = bvNone
+        ClientHeight = 34
+        ClientWidth = 525
+        TabOrder = 1
+        object CbSuppressPrevUnit: TCheckBox
+          Left = 11
+          Height = 19
+          Top = 8
+          Width = 139
+          Caption = 'Suppress previous unit'
+          Checked = True
+          OnChange = CbSuppressPrevUnitChange
+          State = cbChecked
+          TabOrder = 0
+        end
+      end
     end
     object tsIntervals: TTabSheet
       Caption = 'Intervals'
@@ -318,7 +336,6 @@ object Form1: TForm1
           'TAChart'
         )
         Align = alClient
-        ParentColor = False
       end
     end
     object tsPosition: TTabSheet
@@ -372,7 +389,6 @@ object Form1: TForm1
         )
         Align = alClient
         Color = clWhite
-        ParentColor = False
         object ChartPositionFuncSeries1: TFuncSeries
           Extent.UseXMax = True
           Extent.UseXMin = True
@@ -403,7 +419,7 @@ object Form1: TForm1
           Width = 128
           Align = alTop
           Caption = ' X axis '
-          ClientHeight = 103
+          ClientHeight = 101
           ClientWidth = 124
           TabOrder = 0
           object seXPosition: TSpinEdit
@@ -461,10 +477,10 @@ object Form1: TForm1
           end
           object cbUnitsX: TComboBox
             Left = 54
-            Height = 21
+            Height = 23
             Top = 29
             Width = 60
-            ItemHeight = 13
+            ItemHeight = 15
             ItemIndex = 0
             Items.Strings = (
               'percent'
@@ -485,7 +501,7 @@ object Form1: TForm1
           Width = 128
           Align = alTop
           Caption = ' Y axis '
-          ClientHeight = 106
+          ClientHeight = 104
           ClientWidth = 124
           TabOrder = 1
           object lblPositionY: TLabel
@@ -535,10 +551,10 @@ object Form1: TForm1
           end
           object cbUnitsY: TComboBox
             Left = 54
-            Height = 21
+            Height = 23
             Top = 29
             Width = 60
-            ItemHeight = 13
+            ItemHeight = 15
             ItemIndex = 0
             Items.Strings = (
               'percent'
diff --git a/components/tachart/demo/axis/main.pas b/components/tachart/demo/axis/main.pas
index c6b09cc427..501402fcde 100644
--- a/components/tachart/demo/axis/main.pas
+++ b/components/tachart/demo/axis/main.pas
@@ -35,6 +35,7 @@ type
     ChartToolsetDateTime: TChartToolset;
     cbStaticX: TCheckBox;
     cbUnitsX: TComboBox;
+    CbSuppressPrevUnit: TCheckBox;
     csStripes: TChartStyles;
     DateTimeIntervalChartSource1: TDateTimeIntervalChartSource;
     gbPositionX: TGroupBox;
@@ -45,6 +46,7 @@ type
     lblUnitsY: TLabel;
     lcsMarks: TListChartSource;
     PageControl1: TPageControl;
+    Panel1: TPanel;
     pnlPosition: TPanel;
     rbPositionBottom: TRadioButton;
     rbPositionLeft: TRadioButton;
@@ -64,6 +66,7 @@ type
     udcsSub: TUserDefinedChartSource;
     procedure cbStaticXChange(Sender: TObject);
     procedure cbStaticYChange(Sender: TObject);
+    procedure CbSuppressPrevUnitChange(Sender: TObject);
     procedure cbUnitsXChange(Sender: TObject);
     procedure cbUnitsYChange(Sender: TObject);
     procedure ChartCustomMarksAxisList1MarkToText(var AText: String; AMark: Double);
@@ -104,6 +107,11 @@ begin
   ChartPosition.AxisList[2].Visible := cbStaticY.Checked;
 end;
 
+procedure TForm1.CbSuppressPrevUnitChange(Sender: TObject);
+begin
+  DateTimeIntervalChartSource1.SuppressPrevUnit := CbSuppressPrevUnit.Checked;
+end;
+
 procedure TForm1.cbUnitsXChange(Sender: TObject);
 begin
   ChartPosition.AxisList[1].PositionUnits := TChartUnits(cbUnitsX.ItemIndex);
diff --git a/components/tachart/tacustomsource.pas b/components/tachart/tacustomsource.pas
index a0bdf2c3fa..3d2593fb07 100644
--- a/components/tachart/tacustomsource.pas
+++ b/components/tachart/tacustomsource.pas
@@ -123,8 +123,8 @@ type
   TBasicChartSource = class(TComponent)
   strict private
     FBroadcaster: TBroadcaster;
-    FUpdateCount: Integer;
   strict protected
+    FUpdateCount: Integer;
     procedure Notify;
   public
     constructor Create(AOwner: TComponent); override;
@@ -156,7 +156,6 @@ type
   strict protected
     FExtent: TDoubleRect;
     FExtentIsValid: Boolean;
-    FUpdateCount: Integer;
     FValuesTotal: Double;
     FValuesTotalIsValid: Boolean;
     FXCount: Cardinal;
diff --git a/components/tachart/taintervalsources.pas b/components/tachart/taintervalsources.pas
index 3fff5836b1..77f898f1f7 100644
--- a/components/tachart/taintervalsources.pas
+++ b/components/tachart/taintervalsources.pas
@@ -375,9 +375,9 @@ end;
 procedure TDateTimeIntervalChartSource.SetSuppressPrevUnit(AValue: Boolean);
 begin
   if FSuppressPrevUnit = AValue then exit;
+  BeginUpdate;
   FSuppressPrevUnit := AValue;
-  InvalidateCaches;
-  Notify;
+  EndUpdate;
 end;
 
 procedure TDateTimeIntervalChartSource.ValuesInRange(