I just stumbled over the following issues with merged projects. I post them here to hopefully help anybode who comes across similar issues. Hope, this is the right place for this.
Hmm, curious. I have a project where the top book contains an ampersand, but the merge works fine in IE11.
Maybe it's specific to the version and output type.
I'm using RH11, generating Multiscreen HTML5.
I'm using RH2015, generating Responsive HTML5.
The problem occurs, if the ampersand is entered into top book of the TOC in the merged project, the one without the actual files, where you just select the project that shall be used. Ampersands directly in the TOCs of the projects doesn't seem to cause problems.
However, I also just detected another problem:
Ah, yes, I always try to avoid anything except a-z, A-Z, 0-9 underscore _ and dash/hyphen - (potayto/potahto ) in file names or anything that might become a filename. This includes most administrative files in Robohelp (Toc file, index file, variable names, etc).
Even though they are allowed in a lot of the administrative stuff in Robohelp I find it's better just not to use them so I don't get into bad habits.