MacBook Pro 15” 2018, OS 10.15. Double clicking does not work

MacBook Pro 15” 2018, OS 10.15. Double clicking doesn't work consistently. Just have to keep clicking until one is recognized. Clicking is unresponsive, most times. Used to be able to double click using one finger, that no longer works. Changed Trackpad setting more times than I care to count. Tried a Bluetooth Apple Mouse and the double-click did not work. All Trackpad and Mouse settings turned off.

After a Restart, and selecting Trackpad then Tap to Click and Secondary Click, it still does not work. Funny, I can select all Menu items with ONE click but not to open a folder or document I need to Select and then use a pop-up menu and select Open.