Sidebar width collapsing - Bug

Every few days on unidentified cause, my sidebar to which I have set a custom width, collapses to minimal width.

Quite annoying because I cannot make it stick… Not sure if this is TotalFinder problem or OS’s… but maybe TotalFinder could even negate this bug in Finder (in case this is the cause).

Mavericks 10.9.5, TotalFinder 1.6.2