Required Application-Specific Settings for Spell Catcher X 10.2.1 and Later on Tiger
First things first - update your Spell Catcher X 10.2 installation to 10.2.3!
Spell Catcher X 10.2.3 was just released, visit our Downloads page and grab it! You should also take a look at what's new.
New in Tiger (but buggy)
There's a new text editing view on Tiger - an editable version of the view that Safari and many other applications use to display web content. Mail (on Tiger) uses these when composing messages. Some Dashboard widgets use these for user-editable content (Stickies for instance).
Unfortunately, these views don't yet support Spell Catcher's "Make replacements directly without backspacing" preference (in the Interactive pane, Typing tab). When Spell Catcher asks the view whether it supports this, the answer is "yes". But the reality is that they don't. Pages 1.x and Keynote 2.x (on Panther as well) also have this problem (which was actually fixed in Pages 2.x and Keynote 3.x).
So you must uncheck this preference specifically for Mail and for Dashboard (and Pages and Keynote as well).
Here's the easiest way to do it:
Open Spell Catcher's Preferences window
If the Applications drawer isn't open, click the Applications icon in the toolbar
If Mail isn't in the list, add it
Select Mail in the list, view the Interactive pane, Typing tab, uncheck "Make replacements directly..."
You must do the same for Pages and Keynote 2 (if you own them and haven't already done so).
It gets a bit trickier for Dashboard widgets - you have to add a normally-hidden application to the list:
Click [+] to add another application to the list in the drawer
Type command-shift-g when the open dialog appears. This lets you navigate by typing in the path to a file or folder
Copy and paste this path into the dialog: /System/Library/CoreServices/Dock.app/Contents/Resources/
Add DashboardClient (double-click it, whatever...) to the list.