While Protecting sheet I've Checked only "SELECT UNLOCKED CELLS"
Here's the file without any protection. Thank you for your time sir.One of the allowed protection options is Use Autofilter… does that work?
Edit post posting: I see there's a combobox at cell B60 of the Att_SUMMARY sheet, and now realise this is what you're referring to.
Your vba code is password protected, and one thing I never do is allow macros to run before I can check the code, so I can't test. Perhaps attach the workbook without this protection?