"Check spelling" examines the text for unknown words.
Within the editor, the usual hotkeys work:

Undo: CTRL+Z	Redo: CTRL+Y
Copy: CTRL+C	Paste: CTRL+V
Home: CTRL+Home	End: CTRL+End

If you discover an interesting format somewhere, just use the "raw" icon to find out how it was done.
In UserPreferences, you can set up the editor to open when you double click a page.
You can subscribe to pages to get a mail on every change of that page. Just click on the envelope at top right of the page.