Password field not shown until alternative user selected

 * slick-greeter version (slick-greeter --version) 1.3.2
 * Distribution - (Mint 17.2, Arch, Fedora 25, etc...) Mint 19.3
 * Graphics hardware *and* driver used: Intel onboard; Mesa
 * 32 or 64 bit: 64

Issue

Upon logging on, the names of my two user accounts were displayed but the password field was not - as it usually is - visible for my main user. Screenshot:

Steps to reproduce

The problem has not occured before; it may not recur again or at least not regularly. But, what I did was: fiddle around with kernels a bit (remove one, install one); reboot. The system was fine once I managed to log in, having got the password field to appear. I achieved the latter by clicking on the name of my second account, which displayed the password field for that account, and then clicking on the name of my first account, whereupon the password field for that account appeared. Simply - initially - clicking the name of the first user account did nothing.

Expected behaviour

The password field should appear automatically - of, if the system for some reason does not know which account I wish to use, then clicking on any of the available account names should work (and I am pretty sure that, this time, it did not).

Other information

Cf. #99.

Review slick-greeter's user-selection flow, beginning with the reported transition from the second account back to the first after reboot. Reproduce the intermittent case if possible; done when the selected user's password field appears automatically and selecting either listed account reliably displays its field.