The Preferences page provides access to display and usability options.

Show Site Header
Enables/disables the optional header and footer images in your web UI display. For more information, see Define and Display a Site Header or Footer for Gerrit Code Review.
Use Flash Clipboard Widget
When enabled, displays a widget on various text fields throughout the web UI that allows you to copy the contents of the field to the clipboard.
Note: Requires a Flash-enabled browser.
CC Me on Comments I Write
When enabled, you will receive an email containing comments that you submit in response to a review request. The default is to have this setting disabled, to reduce the amount of code review email you receive. But if you want e-mailed confirmation of comments published by your account, you have the option of enabling this setting.
Display Patch Sets in Reverse Order
When enabled, reverses the display order of the patch sets in the Change Screen so that the latest patch set is always shown on top. This is useful when there are several patch sets for a change, and the latest patch set and the links to the diffs in the patch set end up below the fold of the Change Screen.
Display Person Name in Review Category
When enabled, displays the name of the last reviewer in the “R” column of theGerrit Code Review Dashboard.
Maximum Page Size
Specifies the maximum number of rows that will be visible in Gerrit Code Review displays.
DateTime Format
Allows you to specify one of four Date formats (Three American, with month then day, using commas, hyphens, or slashes. One European, with day then month, separated by periods), and one of two Time formats (12 hour AM/PM, or 24 hour).