Excel Multi-Select Dropdown Setup

I have an existing Excel workbook and I want to enhance it with a true multi-select dropdown list—something users can click once and then pick multiple values that remain visible in the same cell, separated by commas (or another delimiter you recommend). Native data-validation only allows one choice, so I’ll need a small, reliable VBA routine (or a modern Excel formula approach if you have one that works just as smoothly) wired up and ready to use.

Here’s what I’m aiming for:

• The dropdown should behave intuitively: pick, unpick, and reorder selections without breaking cell formulas or conditional formatting that may reference the cell.
• It must work in the current desktop version of Excel for Windows; if it also runs on Excel for Mac even better, but Windows is the priority.
• No third-party add-ins—just standard Excel features or VBA.
• Clear, in-file comments or a short PDF explaining how to adjust the source list and copy the functionality to other ranges when I need more of these dropdowns in the future.

Once the code is installed and the sample cells demonstrate the multi-select behaviour, I’ll give it a quick test by adding, deleting, and reordering items. If everything behaves as described and there are no security warnings on open, I’ll release the milestone.