Simple, isn’t it ? why do you need to blog about it ? It was my thought til now. but I see its an unanswered question for many..
Highlight dropdown menu and just do ‘PrtSc’ (Print screen button ) .. thats it ? Unfortunately NO . If you press, ‘Prt Scrn’ key, the opened drop down menus collapse back up into its parent tab.
Then what to do ?
If you are using gnome :
Click on ‘Applications’ -> – ‘Accessories’ -> Then application called ‘Take Screenshot’ . There you may see an option called ‘Grab After a delay of ‘0’ seconds. This timer/’second’ field can be edited and changed to something like ‘5’.
once you set it , ‘Click on take Screenshot’ and highlight your dropdown and Wait for automatic screenshot capture..
I am not a kde user, so dont know the exact answer on kde. But, any similar applbication should have similar option.