Recently (a week ago on Friday) some of our users started expressing slow responses in the Magento admin panel dropdown menus when entering orders. Specifically, when they would click a drop down (STATE for instance), the entire drop down would populate, but the ability to select an option from the drop down would be delayed. And the more items in the drop down the longer that delay would be. So when they would click on STATE to select a US state from the drop down for a shipping address, the list would instantly be available, but if they attempted to select an item from the drop down (ALABAMA for instance) it would take 18-20 seconds for the mouse pointer to allow them to select that option. A shorter drop down of say 3 or 4 items would have a 4 or 5 second delay. This does not seem to be related to any code promotion as we had not had one in nearly 2 weeks when this symptom started.
If I logon to the computer as a magento admin, I too see the slowness, so it does not appear to be user/role related. If they logon to MY computer they do not experience the issues. So seems to be computer related, but specific to 4 computers in the organization. I have reinstalled Windows 10 on one of them to no avail. But there is a computer right next to those 4 suspect computers that is an identical Dell with exact same specs. Same CPU, memory, windows version, browser version, etc... And if a user with the issue logs onto that computer there is no drop down menu delays. I have reloaded Windows, performed a system restore to BEFORE the issue started, deleted the Windows user profile and created a new one. This issue is occurring on 4 specific workstations on every browser, Chrome, FireFox and Edge. I am stumped as to what to try next. Any help is greatly appreciated.