I have also experienced this Problem on MacBook Air on MacOS Sierra v10.12.6-
One of the fundamentals of any screen grab tool is to capture drop downs and the like I've come to a complete halt now on an important software training document.
Developers - please contact me as I have worked for the last 20 years on the Interactive Whiteboard and Touchscreen market place and can tell you about some fundamental tools you are missing. It would be useful for example to have a select tool built into the tool bar. I'll explain why when you get in touch. Meanwhile, I'm going to hav