Drag folder from Project Manager to TOC changes topic sequence

I have RoboHelp 2015 V12.0.4.460

I'm creating a TOC. When I drag the folder from Project Manager to the TOC window, the order of the topics is changed. I want them to stay in alphabetical order as they are listed in the Project Manager window. I've gotten it to work before, but can't seem to for this folder.

All suggestions are appreciated.

Thanks,

MDawn