Screen appears frozen

If you are using multiple monitors, it is possible that a property window (that you open for an item in flow diagram) will open on a monitor other than the one where Centerprise Studio is running. As a result  it'll appear as if the screen is frozen. Because a modal dialogue (property window) is open and you must close the property window before you can do get back to the main window. You can drag and bring the property window to the same monitor as the main window.