When you're adding an annotation to the chart it is actually being added to one of two views, depending on whether you specify whether it should be above or below the data:
- SChartAnnotationAboveData - the annotation is added as a subview that is in front of the data.
- SChartAnnotationBelowData - the annotation is added as a subview that is behind your data.
Both of these views are children of the canvas, meaning that the tick marks & labels (which are subviews of the canvas) will be on top of them. The good news is you can simply add the annotations as a subview to the canvas yourself as soon as you've added the annotation: