How to show all combo options if one option is already selected

Suite and Optimus Suite 8
#1

When the combo in my form already have a selected value, the dropdown list shows initially only the selected value.
How can we configure the combo in a way, that all options are shown and the selected one is highlighted?

#2

You can disable the filtering mode with the “readOnly” property:
https://snippet.dhtmlx.com/x22iggo0
or modifying the filtering logic:
https://snippet.dhtmlx.com/cswcxhgb