Excel Table Appears to Automatically Expand but drop down list doesn't update

Hi Willy -

Threadsafe refers to processing that occurs in parallel on two or more processors in the same application.  It is relevant in very fast, real-time applications where two events that need to occur in series, one after the other, can occur in the other order under some circumstances.  Although I didn't read the article in great depth, it appears that the INDIRECT() function in Excel could exhibit a problem in a custom-coded application.

What the INDIRECT function is doing is to use a named reference to return the associated region of cells in the document for use by the data validation feature.  I do not believe that there is any risk in using the INDIRECT function for this purpose.  At most, it would interfere with the validation rule in an unusually-rare circumstance which would be very, very unlikely to happen again.

If custom Visual Basic for Applications code were being written that were making calls to other Application Programming Interfaces (API's) and the calls were being allowed to run on multiple threads, the use of this function might not be a good idea.  In my opinion, there is no risk in using INDIRECT() as I have described it within native Excel formulas.