hints asked for fdo#59727

Hi,

Bug fdo59727 is about addin function MONTHS() that is not interpreted correctly when read from an 
xlsx file.
That is, an xlsx file with the function "MONTHS(...)" opened with calc shows 
"com.sun.star.sheet.addin.datefunctions.getdiffmonths(...)" and understandably results to #NAME? .

The problem also occurs with function WEEKS, but not with OCT2HEX, so not with all addin functions. 
I have not tested with other addin functions.

Hints where to look for the cause are welcome.
I found maAddInMap in  /core/sc/source/core/tool/odffmap.cxx, but don't know where and how this map 
is used to convert to and from xlsx.
This area may be way out my comfort zone, so I'm not sure at all yet whether I want to be the 
assignee for this bug :-)



Winfried