Why does FUNCRES.XLAM open in a seperate window when I open an xlsm workbook

[wtsmith]

I know what the FUNCRESS.XLAM sheet does, I have used it for a long time. In the past when opening an xlsm workbook only the workbook opened. Recently with no changes by me, a second window for FUNCRES.XLAM opens. This is true for existing and new workbooks. If I close it the entire workbook closes and Excel exits. Our corporate office 365 was recently upgraded and I am guessing that the newer version of office has a different default setting but if so I do not know what it is. This is not a big issue but is an annoyance.