Unchecks this fixture's {@link JCheckBox} only if it is checked.
@return this fixture.
@throws IllegalStateException if this fixture's JCheckBox is disabled.
@throws IllegalStateException if this fixture's JCheckBox is not showing on the screen.
All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.