In the past I could always tell when a colleague had a shared file open. I would know not to make changes if the other open file had changes that had not been saved. I use the DropBox app on my Mac running OS 10.10.5 in Safari 10.1.2. My colleague runs in Windows and noticed the same new issue.
How do we change settings or what do we need to do to get that information again? I want to avoid two or more people changing the same file and having to merge documents (mostly Word and Excel).