diff --git a/BeWo/Scheduler/View/NewSchedulerView.xaml b/BeWo/Scheduler/View/NewSchedulerView.xaml
index e23920dad..18a72a65e 100644
--- a/BeWo/Scheduler/View/NewSchedulerView.xaml
+++ b/BeWo/Scheduler/View/NewSchedulerView.xaml
@@ -128,7 +128,7 @@
 					<Grid x:Name="PART_ToolTipContainer" dxsch:SchedulerControl.HitTestType="AppointmentContent" dxsch:SchedulerControl.SelectableIntervalViewInfo="{TemplateBinding ViewInfo}" Tag="{TemplateBinding ViewInfo}">
 						<!-- Region AppointmentToolTip -->
 						<ToolTipService.ToolTip>
-							<ToolTip Content="{TemplateBinding ViewInfo}" ContentTemplate="{Binding ViewInfo.View.AppointmentToolTipContentTemplate, RelativeSource={RelativeSource TemplatedParent}, UpdateSourceTrigger=PropertyChanged}"
+							<ToolTip Content="{TemplateBinding ViewInfo}" ContentTemplate="{Binding ViewInfo.View.AppointmentToolTipContentTemplate, RelativeSource={RelativeSource TemplatedParent}}"
 									 Visibility="{Binding ViewInfo.View.AppointmentToolTipVisibility, RelativeSource={RelativeSource TemplatedParent}, Converter={StaticResource ToolTipVisibilityConverter}}">
 							</ToolTip>
 						</ToolTipService.ToolTip>
@@ -248,7 +248,7 @@
 					</dxschint:AppointmentColorConvertControl.BaseBrushColors>
 					<Grid x:Name="PART_ToolTipContainer" dxsch:SchedulerControl.HitTestType="AppointmentContent" dxsch:SchedulerControl.SelectableIntervalViewInfo="{TemplateBinding ViewInfo}">
 						<ToolTipService.ToolTip>
-							<ToolTip Content="{TemplateBinding ViewInfo}" ContentTemplate="{Binding ViewInfo.View.AppointmentToolTipContentTemplate, RelativeSource={RelativeSource TemplatedParent}, UpdateSourceTrigger=PropertyChanged}"
+							<ToolTip Content="{TemplateBinding ViewInfo}" ContentTemplate="{Binding ViewInfo.View.AppointmentToolTipContentTemplate, RelativeSource={RelativeSource TemplatedParent}}"
 									 Visibility="{Binding ViewInfo.View.AppointmentToolTipVisibility, RelativeSource={RelativeSource TemplatedParent}, Converter={StaticResource ToolTipVisibilityConverter}}">
 							</ToolTip>
 						</ToolTipService.ToolTip>