[Evolution] Some keys not enterable in search?

[Paul Smith <paul mad-scientist net>]

Here's something super-strange: I can't type the numbers 0-5 into the
search bar (the one at the top of the vertical view showing both
subjects and message preview) in Evolution!!

Can anyone else see this? I can enter all the alphabetic and special
characters that I tried, plus the numbers 6, 7, 8, and 9, but not 0
through 5...?!?!?! It does work to enter the special characters )!@#$%
(shifted 0-5). Of course, the numbers work fine elsewhere.

I'm using Ubuntu 17.10 / Evolution 3.26.1.