What is this annoying popup when I try to edit text: Recently in some apps when I select a word to edit it, I sometimes (not always) get this annoying popup:



Once this popup appears, I cannot edit the text selected, and have to click away from it and start again. Where does this come from, and can I suppress it? 

The exact behaviour is: I select text by sweeping with the mouse. Then I move the cursor back into the selected text without touching any mouse button. As soon as the cursor is in the selection and before I can click a button, the popup appears. The same thing happens using my trackpad
This appears to be coming from the productivity app Things 3.  You may have this in your login items (Settings → Users &amp; Groups → User → Login Items).  Disable it there to prevent it from automatically starting.

Their support site has a great deal of info on how to use the product, but I was unable to find anything on preferences/settings.  There should be something in their settings that enables/disables actions when you select text.  

If you have further difficulty, you may wish to contact that developer directly through their website: https://culturedcode.com/things/support/