Pressing tab in file search box does not iterate through the fields

Describe the bug
Pressing tab in file search box (Cmd+f) does not iterate through the fields, forcing you to use the mouse if you want to interact with the search box fields.

To Reproduce
Steps to reproduce the behavior:

1. Cmd+f to open the file search box
2. Press tab to iterate through the fields
3. Notice that tab only jumps from the search input to the first button. Pressing tab further does not jump to the next buttons nor Shift+Tab jumps back to the input field.
4. Also notice that if you're on the input field, pressing Shift+Tab does not focus the arrow button before it to open the replace input field.

Expected behavior
I would expect the same behavior as when Vim is disabled: pressing Cmd+f opens the file search box, Shift+Tab focuses the arrow before the search input field (that opens the replace input field) and Tab focuses the next field (or button) in the sequence going all the way around.

• Extension (VsCodeVim) version: 1.13.1
• VSCode version: Insiders 1.44.0
• OS: macOS 10.15.4

Start by reproducing the Cmd+f file search behavior in VS Code with the Vim extension enabled, then compare it with Vim disabled as described. Trace the extension's keyboard and focus handling for the search and replace controls; done means Tab and Shift+Tab move through all fields and buttons in both directions.