Dear,
When creating tasks with the "create" button or with 'enter' at the end of the gantt chart, the tasks are not (always) saved/created in Odoo.
For the create button it sometimes works and sometimes doesn't. With enter at the end of the list, the new tasks get WBS number 2, 3 etc. instead of 1.13, 1.14 etc.
When closing the gantt view and reopening it, the tasks disappear. Also, the tasks are not shown in the tree or kanban view of Odoo, which clearly shows they are not created in Odoo.
A video shows this behavior in the demo.