Bug: tooltip for sort titles says %{field_lower_first} instead of correct column name

[arnowelzel]

When hovering a column in a table so the mouse is over the sort icon, the tool tip seems to be broken. It says "sort by %{field_lower_first} ascending" or "sort by %{field_lower_first} descending" where %{field_lower_first} should be the column name.

Example: this should be "sort by Name ascending"