It's possible to customize the position of the as-you-type context menu so when suggestions are displayed the menu strip is located in a specific position. This example demonstrates how to lower the suggestions strip by 20 pixels so the misspelled word is not covered when suggestions are shown;
Add this line
this.aytRichTextBox1.ContextMenuStrip.Opened += new EventHandler(ContextMenuStrip_Opened);
With event handler
void ContextMenuStrip_Opened(object sender, EventArgs e)
(sender as ContextMenuStrip).Top += 20;
Where aytRichTextBox1 is the textbox being spell checked.