Abiword "supported" ligatures back when I used it. It didn't consider them in font width calculations, though, which made the light-gray whitespace dots further to the right. I switched to libreBROffice since, because even after numerous "releases" that particular issue didn't get addressed. Thinking back, I might have been able to turn off ligatures in some obscure or not so obscure place, but never took the opportunity to figure that out.
cheers! mar77i