In XYZ.xla, I have seven functions named XYZ1 through XYZ7.

XYZ1 through XYZ6 execute successfully and return expected results. They
also display in the Excel cell as Upper Case; regardless of whether they're
keyed-in as lower or upper case.

XYZ7, also, executes successfully and returns the expected result. However,
whether keyed-in in lower or upper case, it displays in its cell as "xyz7"
instead of "XYZ7". What might cause this reversion to lower case of a UDF
name?