## Implementation Summary Added E2E test file tests/e2e/test_update_issue_clear_assignee_to_null.py with 4 test cases: ### Test Cases 1. test_update_issue_clear_assignee_to_null - Verifies clearing an assignee on an issue with an existing assignee via the detail modal PropertyDropdown 2. test_update_issue_clear_assignee_and_verify_ui_update - Verifies the UI correctly reflects the unassigned state after save 3. test_update_issue_change_assignee_then_clear - Verifies changing to a different assignee then clearing entirely 4. test_update_issue_clear_assignee_dropdown_shows_no_assignee_option - Verifies No assignee option is always visible in dropdown ### Verification All 4 tests pass locally with E2E server. 8 related assignee tests also pass.