I just upgraded to the latest macOs Sierra. Since then when I click the icon to select area to take screenshot of nothing happens.
I am using V3 of Dropshare.
Dropshare for Mac 3 is not officially compatible with Mac OS X Sierra. We suggest to upgrade to version 4.
Upgraded to v4 all working now.
Thanks for your help.
ps: Might be a good idea to update your website about 3 not being compatible with Sierra. May expedited upgrades for you too