Currently, only a few of the mistkaes are shown in the "Not In Dictionary" box. Once a word is changed or ignored, new ones are added. When the number increases, words from the beginning are removed.
This property/method should let the spell control show all the text at once.

The default focus in the dialog should provide a meaningful action if enter is pressed. The Ignore button would be one such. If you feel like another button/element should have the default focus, share your comments. You can find attached a sample that provides tabIndexes and default focus. This improvement is related to http://feedback.telerik.com/Project/108/Feedback/Details/126937