@Emily_Rockwood I believe this is the case because if you were to move a task from a project to become a “subtask of” then it isn’t technically multihomed to that project any longer. Subtasks are only indirectly associated with a project. Now, I believe you can do this but only if the task is a parent task in one project and a subtasks in another. Essentially, a subtask can only be a subtask in one place (it’s home base). That subtask can be multihomed to 20 other projects however (just at the root level, in and out of a section. Let me see if I can prepare a quick screencast to demonstrate.