​@rzb1qs - the system only removes the activity from the timesheet AND Select Work screen when the work status has been set to something like Completed or Canceled (based on the status rules set in your system). This is to allow a resource to track time to a project in the event that a PM has not kept their allocation up to date, or maybe there is unexpected work. I believe the thought is that we don’t want to prevent a resource from tracking time if they truly were working on the project. 

This means if the activity the resource(s) is assigned to is a long lasting one where resources come and go then it will remain selectable in their Select Work until the time the work status changes. 

If this causes too many issues you may look at using Reserves coupled with Authorizations because authorizations are impacted by the dates that are set on them, however this option does come with its own downfalls too like the resource not being able to see remaining effort on their timesheet or the need to change how Reserves are handled during progression. 

Thank you Pam for the input.  I will have to think about the available solutions.  Based on how we are currently doing resource management (at a higher level and not at a task by task level), the completed / cancelled option would not be a good solution.  We were using reserves prior, and this created issues with our overall res mgt process (use issue not tool issue).  I may come back with some additional questions.  Thanks again.