System 7.5.5 Update -- It's clear now that Apple has not yet released System 7.5.4, and in fact, according to sources, is fixing problems relating to the IR capabilities of some Macs. The update, when it comes out, will be renumbered to 7.5.5. The next mention of it in TidBITS will be when it's actually available. [ACE]
Turn Off Filename Extension Warning
In Leopard, Apple fixed an annoying aspect of working with the Finder in Tiger. Previously, if you changed a file's extension, the Finder prompted for confirmation. But since no one has ever accidentally changed a filename extension, Apple thankfully added an option to turn that warning off in the Leopard Finder's preferences. Choose Finder > Preferences, and in the Advanced screen, deselect Show Warning Before Changing an Extension.