It was on the grid but greyed out and with a question mark on top.
I rebooted, deleted all prefs, rebooted again and tried from scratch but nothing came up .

I figured out another solution: found the Airdrop app in System library and added that one

The upgrade to Dropzone 4 is not in my wallet: too many other expenses
and Dropzone has everything I need for now. Well done app.

I cannot add a new Airdrop action to Dropzone: it doesn't show any
I've tried to delete the one that was giving an error and a question mark after the upgrade

Deleted all prefs and installed a new one

I gave all the possible permissions . And of course I'm able to airdrop from my computer to my devices

I read that it should be part of Dropzone itself but it doesn't show when I click the + sign on the left top of Dropzone
Is there any other way to add it? Am I missing something?

Thanks in advance