Organizer Action Items Filter By shows Project Name in the drop down list. It does not filter Action Items by projects.
All
Project name shows up in Organizer Action Items Filter By list if the Project is added to My Projects list.
Remove the Project from My Projects and the Project gets removed from the Organize - Action Items - Filter By List
1) Go to the Project which is showing up in the drop down
2) Click on Actions drop down
3) Click on Remove from My projects
This will remove the project from Organize - Action Items - Filter By List