I need to insert activities that occur every x time in the graph: ex. every week, every 3 days, every month, etc. I’ve seen the Gantt_DateDependentBackground example that has a similar behaviour but when i maximize the window, for example, the background is drawn also on the timeline. Also in that way the user is not able to select that objects in the graph and i’d need to implement a custom management of this activities for theirself
Using the techniques shown in the Gantt_DateDependentBackground sample is one way to go (this samples had some issues that has been corrected in newer assemblies, see the info node on download info), but you can also add separate time items to show these items. You can add them to another drawing layer if you want to control the z-order between these two types of time items. You can have one databound list of time items per time item layer.
But if you choose to go on the “dead-drawing” solution, you can still catch mouse events in the time item area and use the PixelToDate to convert a pixel on the time item area to the corresponding date time. This way you can calculate if the user clicked one of your drawn areas.