a smart prop is locked to the parent such that moving the figure (or the specific part of the figure the prop is parented to) will move the prop with it. as mentioned above, the parent figure has to be loaded into the scene before the prop. if you're not sure whether your prop is correctly locked to the parent figure, move the figure. if the prop is left behind, it's not "smart". this can be confusing when the prop appears to load in the proper position. but only a smart prop will both load properly and lock to the parent. the only way to be sure is to move the parent.