How to set initial value of InstallFolder Editbox component in BootstrapperApplication ?

[curunoir]

Hi
according to the documentation schema saying that Editbox component can reference a string by StringId attribute I couldn't get it working. This is how I tried it. I used Wix v4 on .net core 7.

Create a custom theme for BootstrapperApplication where you want to set the default value of existing InstallFolder Editbox component to be shown
<Theme xmlns="http://wixtoolset.org/schemas/v4/thmutil">
<String Id="8">C:/temp</String>
<Editbox Name="InstallFolder" X="200" Y="121" Width="-91" Height="21" TabStop="yes" FontId="7" FileSystemAutoComplete="yes" StringId="8"/>

When I'm building it and launch it, the EditBox is not populated with "C:/temp". Am I missing something or is the StringId attribute not working ?