Copy/move multiple filenames into one leads to concatenation
According to current functionality, trying to copy/move multiple marked filenames into a single one pops-up error window You cannot move or copy more than one file to a single file!.
Instead, confirmation box You are merging NNN files into single file 'filename.ext'. Continue? [Yes]/[No] could appear.
Confirmation could be turned off in Options dialog, Misc. section.
Implementation alternatives - Functionality can be restricted either to files inside single directory only or also files in marked subfolders could be concatenated.