The Undo command only works when you choose it immediately after the action you want to cancel. Most dialog boxes contain Cancel buttons. If you click on the Cancel button, the dialog box goes away, returning to where you were before the dialog box appeared. When an application is opened, part of your computer's memory is set aside for use by that application. If you want a program to work with more or larger documents, you can increase the amount of memory it uses.
Most applications have a minimum requirement.
Click once on the application's icon to select it. You must click on the application, not its alias. Open the File menu and choose Get Info . Click in the Preferred size box and type a new number. Try doubling the Suggested Size number.