The cause is having Linux Package "ibus" installed without having "ibus-gtk3" installed.
Solution install package "ibus-gtk3" (I also installed package "ibus-gtk"; not sure if needed.)
I needed to reboot the computer before the problem went away.
Found solution here
https://bugs.launchpad.net/ubuntu/+source/gnucash/+bug/1306500except they only said to install "ibus-gtk".
Problem happened on Linux Debian "Jessie" for me. Using Code::Blocks linked to wxGTK3.
Tim S.