Pale colors in tabs when restoring previous state

I have noticed a strange problem, that I describe in the following. If I have the preference option “Restore Previous Window on Start” enabled (“yes” value) then the colors of my tabs are very pale when I open Atom: the problem keeps itself even if I open new tabs in the following. This problem does not happen if “Restore Previous Window on Start” has the “no” value (in that case, the tabs have the lively and nice colors expected). I am using the package color-tabs and color-tabs-regex, but they do not seem to affect this problem: if I disable them both I can still notice the same strange behavior (pale tabs when automatic restoring is enabled).

Any idea or tip is welcome.