Hi BVS Rao,
This feature is not offered by RadSpell out-of-the box. The only way to remove misspelled words from the custom dictionary is to open the custom.txt file placed in ~/App_Data/RadSpell and edit it.
You can write your own code that will load the contents of this TXT file in a multlined textbox control, which will allow the users to edit the custom words, and provide a save button to save the content.
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