Sitefinity 3.X doesn't support such a low resolution for the administration. But in case that using a monitor with 800x600 is imperative you can browse the page with pressing TAB button - in some moment the I'm done
button will be focused and you will be able to press it.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items