Hi, running on OS10.11.6, PM latest build as of tonight.
Prior to the last 2 updates I was able to use the Merge button in Structured Keywords to import a file with the extension TSV as downloaded from Google Sheets. During the last 2 updates, files with this extension are grayed out and unable to be selected for import.
They will import / merge fine if I rename them, but it was much more convenient when I was able to directly merge that file extension.
I suppose I am unsure if this was something you changed or OS X changed.
help.