How to make gksudo or gksu sessions last longer in Linux

Every time I want to open a GUI program that needs root permissions, I have to put my password. For example, I open synaptic and put my password then close it and a second later decide to reopen it it asks for the password again. Ubuntu 9.04 wasn't like that, it had a timeout of around 1 minute between sessions. I would like that again on the newer version of Linux. I know how to make sudo sessions last longer in Linux. All I have to do is type: sudo visudo then change: Defaults env_reset to (3 minutes): Defaults env_reset,timestamp_timeout=3 Is there a similar way to change the gksu session's timemouts?