How do I compress the PL by Category view?

This view shows your Departments as Rows, and your Categories/Accounts as columns.

Often, in the PL by Category view, you won't want to see a column for every category.

There is a menu at the top left that allows you to choose which categories to view, but if you want to see your total P+L and don't need to see all the category detail, you need to go to Settings > Preferences and uncheck the Show Category in PL by Category Dashboard box.