Spell and Grammar Check
If you want, you can wait until you've finished working on a document to check spelling and grammar.
If you see in the lower-right of the Status bar, you know you have mistakes to correct.
As you type, a check mark moves from page to page on the book icon. When you stop typing, a red check mark remains, telling you no spelling errors were detected by automatic spell checking.
If an X appears on the book icon, it indicates that mistakes exist in your document.