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