Default Icon Size enables you to change the default size of all States in the State Transition Diagram.
Choose Small, Medium, Large or Variable in the popup window.
If you selected Small, Medium, or Large all States appear in the new size.
If you selected Variable, then you can change the size of the States with the mouse. Press the left mouse button and drag the slider to the required size.
When you have finished, click on OK to make the changes or Cancel to keep the current sizes.