Settings

Separate advanced preferences from frequently used ones. However make sure to present the advanced preferences in context.

Either let users apply changes instantly. Or offer an explicit apply mechanism.

Present categories in columns rather than trees.

Place the controls that manipulate the list below the list.

Group Settings that belong together. Give that group a short and descriptive label. Omit orphaned settings.

To present the main settings navigation put two panels next to each other - ideally in a horizontal layout. One of them contains the labels of the main settings navigation. The other one displays the content of the selected entry.

Offer a way to undo the changes users made to the settings. The undo mechanism should cover undoing the most recent changes as well as resetting to the defaults settings.

Labels can be best scanned if they are right aligned.