Keybase main window won't open again after closed the first time

On Kubuntu Linux 18.04.1, running Keybase:

Client: 2.8.0-20181008202958+7cf71f6fcb
Service: 2.8.0-20181008202958+7cf71f6fcb

my log id: 221411692590bfdc8de4231c

Upon starting Keybase with the default login autostart under KDE, it starts normally, but if I open the main window with the popup menu, it only opens once. Upon closing it, it won't open again until the application is quit and restarted.

Upon restarting the application, the window may be opened repeatedly without issue, but there is still a minor issue likely unrelated to this: The notification area icon is twice as large as it should be, and appears to be cropped to just the center 50% of the actual icon.

Reproduce the main-window reopening failure on Kubuntu Linux 18.04.1 with the reported Keybase client version, using log ID 221411692590bfdc8de4231c as a reference. Check both repeated reopening after closing and the oversized, cropped notification icon; done means the window can reopen repeatedly and the icon displays at the expected size.

Written by the indexing model from the issue text.