Insertion point should stay inside Script Picker

[nhnicwaller]

It's possible to move the insertion point from the script picker into the document below, but this is never the expected or desired behaviour for me.

Expected Result:

• If the picker is open and empty, pressing Tab should expand the list to display all available commands (a bit like command auto-completion in the shell).
• If the picker is open and contains text and results are available, pressing Tab should move the selection down the list just like pressing the down arrow. Or press Shift-Tab to move the selection up.
• If the picker is open and contains text and no results are available, pressing Tab should do nothing.

Actual Result:

• If the picker is open pressing Tab once makes the insertion poing disappear. Pressing it a second time moves the insertion point into the document below. ❗
• Once the insertion point has moved to the document below, it cannot be returned to the picker by pressing either Shift-Tab or Cmd-B. ‼️ The only way to escape is by pressing Esc (naturally).