Hi Cemil,
We have analyzed your query and with use of SplitterSettings we are not able to reproduce this issue. From your attached screen shot we noticed some issues.
- You have used both DataSource and DataManager
- In GanttTaskFields, you are not mapping either SubTasks or ParentID field.
For data binding, either we have to bind data using DataManger or DataSource. No need to bind both configurations. Please refer the below UG link for data binding.
And you have done some customization using GanttTemplates and RowSelected and OnActionBegin events. So, can you please share small video regarding the reported issue and if possible, can you please share issue reproducible sample? It will more helpful to resolve your query with the help of code that you used in GanttTemplates and events.
Regards,
Logeswari G