I159-Fix tooltip background was not updated when the theme was changed.

maui/src/Charts/Behaviors/ChartTooltipBehavior.cs

@@ -68,7 +68,7 @@ public partial class ChartTooltipBehavior : ChartBehavior, IParentThemeElement
             null,
             BindingMode.Default,
             null,
-            defaultValueCreator: BackgroundDefaultValueCreator);
+            null);
 
         /// <summary>
         /// Identifies the <see cref="Duration"/> bindable property.
@@ -98,7 +98,7 @@ public partial class ChartTooltipBehavior : ChartBehavior, IParentThemeElement
             null,
             BindingMode.Default,
             null,
-            defaultValueCreator: TextColorDefaultValueCreator);
+            null);
 
         /// <summary>
         /// Identifies the <see cref="Margin"/> bindable property.
@@ -125,7 +125,7 @@ public partial class ChartTooltipBehavior : ChartBehavior, IParentThemeElement
             nameof(FontSize),
             typeof(float),
             typeof(ChartTooltipBehavior),
-            14f,
+            float.NaN,
             BindingMode.Default,
             null);
 
@@ -738,16 +738,6 @@ void Tooltip_TooltipClosed(object? sender, TooltipClosedEventArgs e)
             return view;
         }
 
-        static object TextColorDefaultValueCreator(BindableObject bindable)
-        {
-            return Color.FromArgb("#F4EFF4");
-        }
-
-        static object BackgroundDefaultValueCreator(BindableObject bindable)
-        {
-            return new SolidColorBrush(Color.FromArgb("#1C1B1F"));
-        }
-
         #endregion
 
         #endregion

maui/src/Charts/ChartBase.cs

@@ -117,6 +117,7 @@ public abstract class ChartBase : View, IContentView, IChart
 			typeof(ChartBase),
 			null,
 			BindingMode.Default,
+			null,
 			null);
 
 		/// <summary>
@@ -603,7 +604,6 @@ protected override void OnPropertyChanged([CallerMemberName] string? propertyNam
 					continue;
 				}
 
-				SetDefaultTooltipValue(behavior);
 				var tooltipInfo = chartSeries.GetTooltipInfo(behavior, x, y);
 				if (tooltipInfo != null)
 				{
@@ -682,7 +682,6 @@ public void SaveAsImage(string fileName)
 					if (_defaultToolTipBehavior == null)
 					{
 						_defaultToolTipBehavior = new ChartTooltipBehavior();
-						SetDefaultTooltipValue(_defaultToolTipBehavior);
 						_defaultToolTipBehavior.Chart = this;
 						// defaultToolTipBehavior.IsDefault = true;
 					}
@@ -698,13 +697,6 @@ public void SaveAsImage(string fileName)
 			}
 		}
 
-		internal void SetDefaultTooltipValue(ChartTooltipBehavior behavior)
-		{
-			behavior.Background = TooltipBackground ?? behavior.Background;
-			behavior.TextColor = TooltipTextColor ?? behavior.TextColor;
-			behavior.FontSize = !double.IsNaN(TooltipFontSize) ? (float)TooltipFontSize : behavior.FontSize;
-		}
-
 		SfTooltip? IChart.TooltipView
 		{
 			get { return _tooltipView; }

maui/src/Charts/Series/BoxAndWhiskerSeries.cs

@@ -1185,14 +1185,13 @@ internal override void GenerateSegments(SeriesView seriesView)
 						Y = yPosition,
 						Index = index,
 						Margin = tooltipBehavior.Margin,
-						TextColor = tooltipBehavior.TextColor,
 						FontFamily = tooltipBehavior.FontFamily,
-						FontSize = tooltipBehavior.FontSize,
 						FontAttributes = tooltipBehavior.FontAttributes,
-						Background = tooltipBehavior.Background,
 						Item = dataPoint
 					};
 
+					UpdateTooltipAppearance(tooltipInfo, tooltipBehavior);
+
 					if (IsOutlierTouch)
 					{
 						tooltipInfo.Text = yValue.ToString();

maui/src/Charts/Series/CartesianSeries.cs

@@ -1340,14 +1340,14 @@ internal bool IsDataInVisibleRange(double xValue, double yValue)
 					Y = yPosition,
 					Index = index,
 					Margin = tooltipBehavior.Margin,
-					TextColor = tooltipBehavior.TextColor,
 					FontFamily = tooltipBehavior.FontFamily,
-					FontSize = tooltipBehavior.FontSize,
 					FontAttributes = tooltipBehavior.FontAttributes,
-					Background = tooltipBehavior.Background,
 					Text = yValue == 0 ? yValue.ToString("0.##") : yValue.ToString("#.##"),
 					Item = dataPoint
 				};
+
+				UpdateTooltipAppearance(tooltipInfo, tooltipBehavior);
+
 				return tooltipInfo;
 			}
 

maui/src/Charts/Series/ChartSeries.cs

@@ -1737,6 +1737,22 @@ internal virtual void GenerateSegments(SeriesView seriesView)
 		{
 		}
 
+		/// <summary>
+		/// Updates the tooltip appearance including background, text color, and font size.
+		/// 
+		/// ChartTooltipBehavior Background with AppThemeBinding · Issue #159 · syncfusion/maui-toolkit
+		/// Resolved the issue where tooltip background doesn't update dynamically by changing the theme when using AppThemeBinding.
+		/// </summary>
+		internal void UpdateTooltipAppearance(TooltipInfo info, ChartTooltipBehavior tooltipBehavior)
+		{
+			if (Chart is ChartBase chart)
+			{
+				info.Background = tooltipBehavior.Background ?? chart.TooltipBackground ?? new SolidColorBrush(Color.FromArgb("#1C1B1F"));
+				info.TextColor = tooltipBehavior.TextColor ?? chart.TooltipTextColor ?? Color.FromArgb("#F4EFF4");
+				info.FontSize = !float.IsNaN(tooltipBehavior.FontSize) ? tooltipBehavior.FontSize : !float.IsNaN((float)chart.TooltipFontSize) ? (float)chart.TooltipFontSize : 14.0f;
+			}
+		}	
+
 		internal virtual void InitiateDataLabels(ChartSegment segment)
 		{
 			if (DataLabels.Count > _segments.Count)

maui/src/Charts/Series/HiLoOpenCloseSeries.cs

@@ -322,14 +322,13 @@ internal virtual void CreateSegment(SeriesView seriesView, double[] values, bool
 					Index = index,
 					Text = (yValue == 0 ? yValue.ToString(" 0.##") : yValue.ToString(" #.##")) + "/" + (lowValue == 0 ? lowValue.ToString(" 0.##") : lowValue.ToString(" #.##")) + "/" + (openValue == 0 ? openValue.ToString(" 0.##") : openValue.ToString(" #.##")) + "/" + (closeValue == 0 ? closeValue.ToString(" 0.##") : closeValue.ToString(" #.##")),
 					Margin = tooltipBehavior.Margin,
-					TextColor = tooltipBehavior.TextColor,
 					FontFamily = tooltipBehavior.FontFamily,
-					FontSize = tooltipBehavior.FontSize,
 					FontAttributes = tooltipBehavior.FontAttributes,
-					Background = tooltipBehavior.Background,
 					Item = dataPoint
 				};
 
+				UpdateTooltipAppearance(tooltipInfo, tooltipBehavior);
+
 				return tooltipInfo;
 			}
 

maui/src/Charts/Series/PieSeries.cs

@@ -1,4 +1,5 @@
 using System.Collections.Specialized;
+using Microsoft.Maui.Controls;
 using Syncfusion.Maui.Toolkit.Graphics.Internals;
 
 namespace Syncfusion.Maui.Toolkit.Charts
@@ -642,15 +643,14 @@ internal override void SetIndividualPoint(object obj, int index, bool replace)
 				Y = yPosition,
 				Index = index,
 				Margin = tooltipBehavior.Margin,
-				TextColor = tooltipBehavior.TextColor,
 				FontFamily = tooltipBehavior.FontFamily,
-				FontSize = tooltipBehavior.FontSize,
 				FontAttributes = tooltipBehavior.FontAttributes,
-				Background = tooltipBehavior.Background,
 				Text = yValue.ToString("#.##"),
 				Item = dataPoint
 			};
 
+			UpdateTooltipAppearance(tooltipInfo, tooltipBehavior);
+
 			return tooltipInfo;
 		}
 

maui/src/Charts/Series/PolarSeries.cs

@@ -866,14 +866,13 @@ internal void UpdateAssociatedAxes()
 					Y = yPosition,
 					Index = index,
 					Margin = tooltipBehavior.Margin,
-					TextColor = tooltipBehavior.TextColor,
 					FontFamily = tooltipBehavior.FontFamily,
-					FontSize = tooltipBehavior.FontSize,
 					FontAttributes = tooltipBehavior.FontAttributes,
-					Background = tooltipBehavior.Background,
 					Text = yValue.ToString("#.##"),
 					Item = dataPoint
 				};
+
+				UpdateTooltipAppearance(tooltipInfo, tooltipBehavior);
 				return tooltipInfo;
 			}
 

maui/src/Charts/Series/RadialBarSeries.cs

@@ -764,14 +764,13 @@ internal override void OnSeriesLayout()
 				Y = yPosition,
 				Index = index,
 				Margin = tooltipBehavior.Margin,
-				TextColor = tooltipBehavior.TextColor,
 				FontFamily = tooltipBehavior.FontFamily,
-				FontSize = tooltipBehavior.FontSize,
 				FontAttributes = tooltipBehavior.FontAttributes,
-				Background = tooltipBehavior.Background,
 				Text = yValue.ToString("#.##"),
 				Item = dataPoint
 			};
+
+			UpdateTooltipAppearance(tooltipInfo, tooltipBehavior);
 			return tooltipInfo;
 		}
 

maui/src/Charts/Series/StackingAreaSeries.cs

@@ -542,15 +542,13 @@ internal override bool IsIndividualSegment()
 					Y = yPosition,
 					Index = index,
 					Margin = tooltipBehavior.Margin,
-					TextColor = tooltipBehavior.TextColor,
 					FontFamily = tooltipBehavior.FontFamily,
-					FontSize = tooltipBehavior.FontSize,
 					FontAttributes = tooltipBehavior.FontAttributes,
-					Background = tooltipBehavior.Background,
 					Text = content.ToString(),
 					Item = dataPoint
 				};
 
+				UpdateTooltipAppearance(tooltipInfo, tooltipBehavior);
 				return tooltipInfo;
 			}
 

maui/src/Charts/Series/StackingColumnSeries.cs

@@ -596,14 +596,12 @@ internal override void SetTooltipTargetRect(TooltipInfo tooltipInfo, Rect series
 					Y = yPosition,
 					Index = index,
 					Margin = tooltipBehavior.Margin,
-					TextColor = tooltipBehavior.TextColor,
 					FontFamily = tooltipBehavior.FontFamily,
-					FontSize = tooltipBehavior.FontSize,
 					FontAttributes = tooltipBehavior.FontAttributes,
-					Background = tooltipBehavior.Background,
 					Text = content.ToString()
 				};
-				;
+
+				UpdateTooltipAppearance(tooltipInfo, tooltipBehavior);
 				tooltipInfo.Item = dataPoint;
 
 				return tooltipInfo;

maui/src/Charts/Series/StackingLineSeries.cs

@@ -505,15 +505,13 @@ internal override void DrawDataLabels(ICanvas canvas)
 					Y = yPosition,
 					Index = index,
 					Margin = tooltipBehavior.Margin,
-					TextColor = tooltipBehavior.TextColor,
 					FontFamily = tooltipBehavior.FontFamily,
-					FontSize = tooltipBehavior.FontSize,
 					FontAttributes = tooltipBehavior.FontAttributes,
-					Background = tooltipBehavior.Background,
 					Text = content.ToString(),
 					Item = dataPoint
 				};
 
+				UpdateTooltipAppearance(tooltipInfo, tooltipBehavior);
 				return tooltipInfo;
             }
 

maui/src/Charts/SfFunnelChart.cs

@@ -1199,19 +1199,18 @@ void IPyramidChartDependent.OnSelectionBehaviorPropertyChanged(object oldValue,
 				object dataPoint = _actualData[index];
 				double yValue = _yValues[index];
 				var segment = (FunnelSegment)_segments[index];
-				SetDefaultTooltipValue(behavior);
 
 				TooltipInfo tooltipInfo = new TooltipInfo(this)
 				{
 					X = segment.SegmentBounds.Center.X + (float)_seriesBounds.Left,
 					Y = segment.SegmentBounds.Center.Y + (float)_seriesBounds.Top,
 					Index = index,
 					Margin = behavior.Margin,
-					TextColor = behavior.TextColor,
+					TextColor = behavior.TextColor ?? TooltipTextColor ?? Color.FromArgb("#F4EFF4"),
 					FontFamily = behavior.FontFamily,
-					FontSize = behavior.FontSize,
+					FontSize = !float.IsNaN(behavior.FontSize) ? behavior.FontSize : !float.IsNaN((float)TooltipFontSize) ? (float)TooltipFontSize : 14.0f,
 					FontAttributes = behavior.FontAttributes,
-					Background = behavior.Background,
+					Background = behavior.Background ?? TooltipBackground ?? new SolidColorBrush(Color.FromArgb("#1C1B1F")),
 					Text = yValue.ToString("#.##"),
 					Item = dataPoint
 				};

maui/src/Charts/SfPolarChart.cs

@@ -881,7 +881,6 @@ protected override void OnBindingContextChanged()
                         continue;
                     }
 
-                    SetDefaultTooltipValue(behavior);
                     TooltipInfo? tooltipInfo = chartSeries.GetTooltipInfo(behavior, x, y);
 
                     if (tooltipInfo != null)

maui/src/Charts/SfPyramidChart.cs

@@ -1223,18 +1223,18 @@ internal override void UpdateLegendItems()
 				object dataPoint = _actualData[index];
 				double yValue = _yValues[index];
 				var segment = (ChartSegment)_segments[index];
-				SetDefaultTooltipValue(behavior);
+
 				TooltipInfo tooltipInfo = new TooltipInfo(this)
 				{
 					X = segment.SegmentBounds.Center.X + (float)_seriesBounds.Left,
 					Y = segment.SegmentBounds.Center.Y + (float)_seriesBounds.Top,
 					Index = index,
 					Margin = behavior.Margin,
-					TextColor = behavior.TextColor,
+					TextColor = behavior.TextColor ?? TooltipTextColor ?? Color.FromArgb("#F4EFF4"),
 					FontFamily = behavior.FontFamily,
-					FontSize = behavior.FontSize,
+					FontSize = !float.IsNaN(behavior.FontSize) ? behavior.FontSize : !float.IsNaN((float)TooltipFontSize) ? (float)TooltipFontSize : 14.0f,
 					FontAttributes = behavior.FontAttributes,
-					Background = behavior.Background,
+					Background = behavior.Background ?? TooltipBackground ?? new SolidColorBrush(Color.FromArgb("#1C1B1F")),
 					Text = yValue.ToString("#.##"),
 					Item = dataPoint
 				};

maui/tests/Syncfusion.Maui.Toolkit.UnitTest/Chart/DefaultTests/BehaviorDefaultTests.cs

@@ -54,13 +54,11 @@ public void ChartTooltipBehaviorDefaultTests()
 			var behavior = new ChartTooltipBehavior();
 
 			// ChartTooltipBehavior specific properties
-			Assert.NotNull(behavior.Background);
-			Assert.IsType<SolidColorBrush>(behavior.Background);
-			Assert.Equal(Color.FromArgb("#1C1B1F"), ((SolidColorBrush)behavior.Background).Color);
+			Assert.Null(behavior.Background);
 			Assert.Equal(2, behavior.Duration);
-			Assert.Equal(Color.FromArgb("#F4EFF4"), behavior.TextColor);
+			Assert.Null(behavior.TextColor);
 			Assert.Equal(new Thickness(0), behavior.Margin);
-			Assert.Equal(14f, behavior.FontSize);
+			Assert.Equal(float.NaN, behavior.FontSize);
 			Assert.Null(behavior.FontFamily);
 			Assert.Equal(FontAttributes.None, behavior.FontAttributes);