Can't validate a new folder creation

[dino99]

This system is sharing a /home partition with other installations, which also have evolution installed.

Reviewing today mailings list, i've decide to create a new folder to move mail into. The creation steps works as expected except the last one: the 'create' button stay greyed and inactive, no matter of the name folder spelling or its lenght. The result is always the same, no matter from which place you try creating that new folder (top menu, mail context, folder tree).

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: evolution 3.26.2-1
ProcVersionSignature: Ubuntu 4.13.0-16.19-generic 4.13.4
Uname: Linux 4.13.0-16-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.1
Architecture: amd64
CurrentDesktop: GNOME
Date: Sun Nov 5 15:28:58 2017
SourcePackage: evolution
UpgradeStatus: No upgrade log present (probably fresh install)