I just upgraded from 2018.1.3 to 2018.1.4. I'm noticing a new issue every time I use the keyboard shortcut for View->Quick documentation. After I press <ESC> to exit the popup, the keyboard focus is lost. This did not occur under 2018.1.3. This issue also does not occur if you use the mouse to bring up View->Quick Documentation.
The workaround is to use the mouse and click somewhere, but I would prefer to use the keyboard and not the mouse in this case.
Is this a known issue with the upgrade?