To remove it, right-click anywhere on the bookmarks bar and disable "Show Tab Groups." You'll know it's disabled because the button will disappear, and there won't be a check mark symbol next to ...

Search Tabs Button is a new feature introduced in Google Chrome that helps you find the tab by just writing the tab's name in the field.

Certain websites uses JavaScript to automatically force a browser window to take up the whole screen, and the only way to prevent this is to disable JavaScript in the browser options.