I am not sure if you are all seeing the same thing but I use an apple mac and as far as spell checker goes,
What I see underneath a wrongly spelt word is a broken red line. If I right click on the word I get options to change it to the correct spelling or I get a spellchecker option to correct it automatically whilst I type. I do have Office installed on my computer which may help. I have no idea if this is the case in Windows. but will dig the lap top out which runs windows and try it later and report back if its different when using windows operating system.
Ok deleted a little bit in Apple to do a bit on windows format in order to see if that lesa me make spell and it must just be an apple thing as Windows vista lets me do loads of spelling mistakes with no opportunity to fix them If you know what I mean! so the answer is to get an apple. No seriously The windows format is useless while the apple mac must have a built in spell check.
As for delete file this is only an option when you press post…. you will see a preview of your post and at that point you can delete the whole lot. You cannot go on to post and later go back and delete, but you can do an edit later.