Product Version = NetBeans IDE Dev (Build 201209190001)
Operating System = Windows 7 version 6.1 running on x86
Java; VM; Vendor = 1.7.0_07
Runtime = Java HotSpot(TM) Client VM 23.3-b01

I have a module with the following modules:
simple.marauroa.application.core.db
simple.marauroa.application.core.db.controller
simple.marauroa.application.core.db.controller.exceptions
simple.marauroa.application.core.db.manager

If I select all of them as public (Properties>Public Packages) the IDE adds this to the pom:

                     <publicPackages>
                        <publicPackage>simple.marauroa.application.core.db.*</publicPackage>
                    </publicPackages>

Only the package simple.marauroa.application.core.db is displayed as public in the project explorer.

You actually need to close and reopen the module to see the change in the icons. Reloading the POM makes no difference.

Only when I defined them as:

                   <publicPackages>
                        <publicPackage>simple.marauroa.application.core.db</publicPackage>
                        <publicPackage>simple.marauroa.application.core.db.controller</publicPackage>
                        <publicPackage>simple.marauroa.application.core.db.controller.exceptions</publicPackage>
                        <publicPackage>simple.marauroa.application.core.db.manager</publicPackage>
                    </publicPackages>

The change happened on the project editor (had to reopen the module anyway.