In the scenario where the Fluent theme is applied and the MonthViewDefinition'sAllowCustomAppointmentSize property is set to True, appointments with different heights may overlap the expand/collapse RadToggleButton when collapsed.

To work this around, extract the default GroupHeaderStyleSelector for the Fluent theme. Then, extract the Style with x:Key="MonthViewBottomLevelWeekGroupStyle" and modify the Padding property's value. Set this Style to the MonthViewBottomLevelWeekGroupStyle property of the extracted OrientedGroupHeaderStyleSelector (default GroupHeaderStyleSelector). Finally, set an instance of the modified style selector to the GroupHeaderStyleSelector property of RadScheduleView.