Outlook window is small in Citrix ICA

Our remote clients use Citrix to access Email Server, through ICA Program Neighborhood. On one of the clients, the size of Outlook is what a normal window would be if it was minimized. He already tried to change the screen size in his citrix connection but it never worked. A different user logged onto his Citrix and his outlook was full screen. After that, he logged back in Citrix and his Outlook magically was full screen. The next day Outlook was small again. It seems to be his profile in citrix some where??
I checked his infomration on Client Resolution Display. It is 1024×768 with pref 64 K colour depth. Is this a configuration issue or do something else? How do I fix this remotely, in Citrix Server Admin?