Text formatting issue in 4.16

I don't know if this is a known issue or a quirk that I have created but Hype 4.16 is not letting me change the formatting of a block of text on a page.
It's a simple page with a couple of text blocks and a few graphics but the only way I can change the formatting of a block of text is to create a new new box, set the font and colour and then re-type my text. If I just paste in text, it won't let me change it.
What's going on ? Maybe I've got too much formatting going on where I've been changing fonts and sizes. I've tried on two different machines running different systems and it's the same.

Ideas anyone ?

You may be hitting an issue where CSS formatting is coming with your pasted rich text. Please read this page for tips on working with text in Hype: