U

Undo command (Edit menu), 306

uninstalling

extensions, 266

themes, 234

Update tab (Advanced category), 227-228

updating

customizing, 227-228

extensions, 265

Firefox, 209-211

theme compatibility and, 232

themes, 233-234

URLs (Web addresses)

generating shortened, 299-300

keyboard shortcuts for loading, 329-330

manually setting multiple home pages with, 94

phishers inability to copy, 196-198

understanding, 21

U.S. Bank, reporting phishing scams to, 195

US-CERT, 212

user scripts, Greasemonkey and, 292-294

username, setting up Thunderbird account and, 120

Using the Help Window topic, in Help window, 170