Duration: analyse requirements and develop UX concept

Non-working days: analyse requirements and develop UX concept

Update user and admin guides to include duration and non-working days

Quick-add menu not showing on smaller screens

Editing work packages with existing duration results in a validation error

Filters are not working after adding a custom field with default value

Duration error message when trying to create a work package with dates

Can't delete WPs from board view

Insufficient contrast ratio between activity font color and background

SystemStackError (stack level too deep) when trying to assign new parent or children to a work package