Spelling mistakes are extremely difficult to see in onlyoffice. I have attached a screenshot showing this. Spelling mistakes are underlined with a red line that is only 1 pixel thick. This is even more of a problem when you paste a hyperlink in to a document that has a spelling mistake as the whole line is underlined so the only difference is the colour.
Please just use a wavy red line like microsoft office so that spelling mistakes easily stand out - which is the whole point of a spell checker.
