[FEATURE] be able to hide combobox "title"

[jlo62]

Description of the requested feature

I would like to hide the selected text in the combobox menu, like this:
instead of this:

It looks great like the top one until I select something.

It's acceptable with this:

.combo-box-vol > box > button > box > cellview {
  font-size: 0;
  margin: 0;
  padding: 0;
}

but it still has a little notch/margin left.

Or did I overlook a option to hide this?

Proposed configuration syntax

(combo-box-text :show-selected false)

Additional context

No response