creating a multi selection dropdown list

eswestmark 

The article to which you provide a link is not applicable to Excel, but to an old Microsoft product called InfoPath (note the references just below the article title) that creates user data entry forms.

The most direct solutions involve VBA code, which cannot be used with Excel on the web or for the mobile versions.  Also, using VBA code opens you to the possible insertion of malware.  Consider that seriously. 

Depending on what you are trying to accomplish, some design that does not use a multi-selection dropdown list may be possible.  So:

• Is this Excel solution going to be used by just you?  Or by other people (or both you and others)?
• Is the number of selectable items small (say, a dozen or fewer) or large?  Are the items basically static, or dynamic?
• On a broad level, what do you expect to happen when the user selects one or more entries?  E.g., a subset of some data will be displayed, or the user selections will be recorded into a cell.

If you are trying to record multiple values into one cell, VBA might be the best choice.  I do not see any Microsoft documentation regarding this that I would recommend (even their guest blogger article is old and now incomplete).  So consider these:

• Sharon Smith video; code included in video description
• Chester Tugwell video; links to another page with a downloadable (and therefore potentially dangerous) macro-enabled workbook
• Ablebits.com article; code shown on this page