I changed the setting to make my tooltip show on mouse hover. That part works fine.
But my tooltip window shows up for a while, then just disappears, and this happens with I take my hands off the mouse and keyboard and remain mouse-hovered on a ~method.
I tried updating to the latest version (below) and it seemed to fix it for a day, but now again it's back. Of course, it's no fun to have the words disappear as you're reading them.
IntelliJ IDEA 2019.3.4 (Ultimate Edition)
Build #IU-193.6911.18, built on March 17, 2020
Windows 10 10.0