removing squigglelineindicator

Two questions have arisen after recently putting together the starts of a spell checking routine for my implementation of SyntaxEditor.

Firstly, I'm using the example for the VB test application to create a new indicator for underlining spelling errors with a red squiggly line, which works very nicely, however I cannot work out how to remove the indicator if I use the backspace key to correct the spelling error, i.e. After typing 'songsand' I then place the caret at the end of the word and delete back to change the word to 'songs', I then press space and the word is rechecked and deemed to be correct, however I cannot work out how to remove the underline.

Secondly, My spell checking routine is able to determine between HTML, code and plain text so that only strings outside of any code and HTML tags is checked, I would like to extend this to include string definitions within code, specifically javascript "string" 'string' and ASP/VBScript "strings" but it seems that the token for such strings is actually everything between the string identifiers, so that 'string' and 'lots of strings' are detected as a single token. Is it possible to seperate these out as seperate tokens/words like the lixical state 'DefaultState' in HTML or will I need to parse them manually some how?

Thanks for your help