Most operations require toolpath to be a valid operation. Any non-utility operation that has no toolpath is deemed to be incomplete. If you create an operation with no toolpath, then you may encounter problems when trying to select or move the operation tile.
Creating a roughing operation using a tool that is larger than a pocket, will result in no toolpath. Similarly a rough turn operation with the start and end diameters set outside the selected geometry will also result in no toolpath.