Can't filter by string 'date' when adding options in Views

When adding fields, filters, etc., in Views I am unable to use the string 'date' in the Search field to narrow down the available options. This is because the string of searchable text is derived from the input label, which as far as I can tell always contains the word "update".

To reproduce:

1. Edit a view,
2. in the Fields area, click "Add",
3. type "date" into the Search field.

The list should be filtered to only "date"-related options, but instead nothing happens. (I initially thought the keyword search wasn't working at all.)

This problem doesn't exist in 7.x.

Proposed solution: Formulate the searchText from the <td class="title"> element, which does not have "Update " prepended, instead of <label>.

I'll upload a patch in a moment.