The branch filtering feature (JENKINS-35768) has been implemented using a 3rd party "typeahead" control.

The design spec for the "branch filtering" control is similar to the JDL Dropdown and ideally would share much of the same logic. A work-in-progress branch exists to refactor out the Dropdown's menu into a "FlyoutMenu" control that could be reused in different components.

The end state of the code might look something like this:

• Dropdown
  • button (as today)
  • FlyoutMenu
• Typeahead (this might be the name for the control that branch filtering uses)
  • TextInput
  • FlyoutMenu