Question: In MS Word.

If heading one is numbered using roman numbers, when the figure caption also includes chapter numbers, roman numbers will be used like this: "II-1", but what I want is "2-1". How can I achieve this?

![enter image description here](https://i.stack.imgur.com/pO4C2.png)

Answer: 
I've got a better solution: 

Number the chapter headers with Arabic numerals and then use hidden formatting (ctrl+shift+h) to hide the number and manually write "Chapter I", "Chapter II", etc. It's not the prettiest solution, but I think it's the easiest. ToC should use whatever you've written there so you can manually change that too if you need to.
You can right click on the header number and select "adjust list indents" and then check the box that says "Legal Style Numbering". Then you can right click on the style in the ribbon and select "Update X to match section".