When pulling a circle, it changes into a pentagon. When you press the left button of the mouse, the moving surface changes to a circle while the left button is released. The same phenomenon appears when you pull the curve. Is it a computer performance issue? Currently, the computer specifications are windows 8.1 64Bit, Intel (R) Core (TM) i7-4710HQ, CPU @ 2.5GHz, RAM 8.00GB, Intel (R) HD Graphics 4600.