Which .css is better to hide new tab button completely?

[SXZ1]

I want to hide new tab button completely in both overflow mode (sidebar height is not enough to fit all tabs, scrollbar appears) and non-overflow mode (sidebar height is enough to fit all tabs, scrollbar is gone)
First code:

#tabbar:not(.overflow) .after-tabs {
display: none;
}
#tabbar.overflow ~ .after-tabs {
display: none;
}

Second code:

.newtab-button-box {
display: none;
}

[irvinm]

I have also seen:

#tabbar .after-tabs { display: none !important; }

At the end of the day, I am not sure there is much difference between each implementation. I would think your "Second code:" or this one are more simplistic and slightly better.

[wdnz]

I also use the second one without issues.

[piroor]

I think .newtab-button-box { display: none; } is good enough.

[SXZ1]

Thank you very much!