RTC Plans: Time remaining

Hi,

We are using RTC3 IFIX1.
We use Scrum plans.
When a task is "resolved" we "move it to be resolved from the Dashboard view.
1. The time remaining field does not changed to be "=0".
2. From the web - if you would like to set it to be "=0" you do not have this option. the lowest value can be only "=0.5".

Also,
3. from the web you can set value "--" - if you set it you can not save the workitem and will end with errors.

Please advise.