1. A method, comprising: receiving a user input to move a virtual node representing a first value of a first real node from a first hierarchy level in a tree graph to a second hierarchy level, the first value of the first real node corresponding to a first property, the tree graph further including; a virtual node representing a second value of the first real node and included in the second hierarchy level of the tree graph, the second value of the first real node corresponding to a second property, a first branch ending in the first real node, a second branch ending in a second real node, the second real node including first and second values respectively corresponding to the first and second properties, a virtual node representing the first value of the second real node and included in the first hierarchy level of the tree graph, a virtual node representing the second value of the second real node and included in the second hierarchy level of the tree graph, and a root node; identifying the virtual node representing the first value of the second real node and the virtual node representing the second value or the second real node; and organizing the root node, the real nodes, and the virtual nodes of the tree graph, wherein, the virtual node representing the second value of the first real node and the virtual node representing the second value of the second real node are moved from the second hierarchy level, and the virtual node representing the first value of the first real node and the virtual node representing the second value of the second real node are moved from the first hierarchy level.