Hi @AndrewTodd,
I don't know of any Canvas changes that would have affected this behavior in the last few months, nor have I heard anything about this from faculty at the institution I'm an admin at. This does seem like something very browser or add-on specific to me more than something with Canvas itself. @RecycledElectro's suggestion of using a different browser for Canvas might be the easiest thing to do if you can't figure out how to get Chrome to behave the way you'd like anymore.
I know this isn't necessarily the best "solution" but since it's a possibility, I'm going to mark it as such for now. Feel free to continue to give feedback and updates here though!
-Chris