DOpus prompting me to select program for executables on parallels


I'm running Parallels (latest version) on my Mac, and Dopus Pro (v12.9).

When I click on an executable inside DOpus it now prompts me to select a program to open it with! It appears to be the standard windows "How do you want to open the file" dialog. This is any .exe. If I do the inside a normal windows file browser it opens fine.

Any ideas? I have the feeling I've seen this before, but I can't remember (or find) any resolution. It was also working fine the last time I tried this (a while ago - parallels has been updated since then)