Occasionally, misspelled words might not show up as misspelled words for a few seconds. This is due to the checking timer in the spelling engine. In a nutshell, you’re typing faster than the engine can check for misspellings – pause for a second or two and the engine will catch backup up to you and continue checking.
Occasionally, you might see words that are spelt correctly that are underlined – appearing as misspelled. For instance, if you’re typing along and notice a misspelled word at the same time that the computer does and backspace and correct it, the word might still appear as misspelled. This is due to the checking timer in the spelling engine right click the word and the engine will be forced to check it. The underline should then be removed and the word will appear as correct.