I just tried to reproduce these behaviours in our online demo.
After adding a new task to task list, it shows a blank page with word "ok".
Works for me. Can you reproduce this here?
http://www.collabtive.o-dyn.de/demo/If you can, please provide a detailled explanation outlining where you clicked when ect. Maybe you added the task in a specific place?
Also in tasklists window after adding a news task, by pressing the "add task" button it shows all the information of previous task in fields (all information of previous task remains in fields)
This was intentional. But after seeing how it lead to increased confusion instead of helping with productivity (assuming 2 tasks added after each other would often share some characteristics), we are probably going to change this in the upcoming release. The form will be emptied after each submission or cancellation.