We accidentally missed the release of Uncomplex’s Mailplane 2.5 a few weeks ago, which gives the Gmail-specific email client support for full-screen mode in Mac OS X 10.7 Lion, along with support for the new Preview Pane feature from Gmail Labs. Otherwise, the Mailplane 2.5 release fixed bugs relating to Boomerang and Rapportive, addressed some Lion-specific bugs, and automatically adds the Evernote toolbar button when the Evernote application is installed. The just-released Mailplane 2.5.1 adds a Window > Enter Full Screen menu item and keyboard shortcut for Lion users, removes the conflicting keyboard shortcut from Mail > Forward, and fixes some problems with sending messages, uploading attachments, and two-finger swipes in Lion. ($24.95 new, free update, 22.5 MB)
Enabling Auto Spelling Correction in Snow Leopard
In Snow Leopard, the automatic spelling correction in applications is not usually activated by default. To turn it on, make sure the cursor's insertion point is somewhere where text can be entered, and either choose Edit > Spelling and Grammar > Correct Spelling Automatically or, if the Edit menu's submenu doesn't have what you need, Control-click where you're typing and choose Spelling and Grammar > Correct Spelling Automatically from the contextual menu that appears. The latter approach is particularly likely to be necessary in Safari and other WebKit-based applications, like Mailplane.