The above photo shows the problem.
As you can see from the figure, the tabs are grouped together.
How can I isolate them so that they are distributed evenly throughout the space?
You need to edit the user style sheet. In the menu bar, go to "Atom"> "Stylesheet ..." and copy it to the stylesheet file:
.tab-bar .tab { flex-grow: 1 !important; max-width: none; }
After saving, the tabs should be distributed.
This is the best solution: go to Settings> Themes> Theme Settings (the gear icon next to the UI Theme Theme folder) and use the Tab option
source: https://discuss.atom.io/t/the-tabs-got-shorter-in-v1-8-0-what-happened-how-do-i-go-back/29791