The result of:
depends on the Style of the ComboBox.
For the ones that allow you to set the Text to anything other than the items in the list (like the default
csDrowpDown or
csSimple) it will just clear the items but, logically enough, the Text will remain as is. If instead you set Style to, say,
csDropDownList clearing the items will also clear the Text since there is no item from which to get it.
That's one reason why there exists
TComboBox.Clear; whatever the Style it'll clear both the Items and the Text by doing:
procedure TCustomComboBox.Clear;
begin
Items.Clear;
Text:='';
end;
which looks like someone came up against your same problem and added that as a "workaround"