TYPO3 Core

Seems to be due to the height of icons vs. the line-height. The extension-version would have an icon "show all versions", although for some reason here no icon shows up. Is there something like a "line-min-height"? sigh

It is sufficient to add to the arrow icons a vertical-align:middle;
the inspector says:

#terTableWrapper .ui-icon {
  width: 16px;
  height: 16px;
  background-image: url('../../typo3/sysext/extensionmanager/Resources/Public/Images/ui-icons_222222_256x240.png');
  background-position: -64px -16px;
}

but the anchor has class: "versions-all ui-icon ui-icon-triangle-1-s"

so it could become:

#terTableWrapper .ui-icon {
  background-image: url('../../typo3/sysext/extensionmanager/Resources/Public/Images/ui-icons_222222_256x240.png');
  background-position: -64px -16px;
  height: 16px;
  vertical-align:middle;
  width: 16px;
}