[wix-users] dual-mode MSI with per-MACHINE default - how to debug?

[Alan Sinclair]

How do I make a dual-mode installer which has per-MACHINE as the default?
Is it even possible?

I'm using WixUI_Advanced, to get the user's choice of per-user or
per-machine, via InstallScope dialog.

If I use MSIINSTALLPERUSER=1 and ALLUSERS=2 the default is per-user, and
the MSI works as expected, but no other combo works right.

When the default is made to be per-machine, and the user chooses per-user
at the InstallScope dialog, the "Install/InstallNoShield" button is set
correctly but the UAC prompt is always shown.  (I.e. ALLUSERS must have
been set correctly, but something else is triggering UAC prompting)

Is a per-machine default possible on a dual-mode MSI, and if so, how do I
debug this?

Thanks!
Alan

= = = = = == = = = = = = = =

here's minimal code:

<?xml version='1.0' encoding='windows-1252'?>
<Wix xmlns='http://schemas.microsoft.com/wix/2006/wi'>
  <Product Name='Foobar 1.0' Id='DE429F61-F846-4E6F-8873-75D49BB0C3CB'
UpgradeCode='293FF1A9-9298-4CC6-890F-414EA154ACDD'
    Language='1033' Codepage='1252' Version='1.0.0' Manufacturer='Acme
Ltd.'>

    <Package Id='*' Keywords='Installer' Description="Acme's Foobar 1.0
Installer"
      Comments='Foobar is a registered trademark of Acme Ltd.'
Manufacturer='Acme Ltd.'
      InstallerVersion='100' Languages='1033' Compressed='yes'
SummaryCodepage='1252' />

    <Media Id='1' Cabinet='Sample.cab' EmbedCab='yes' DiskPrompt="CD-ROM
#1" />
    <Property Id='DiskPrompt' Value="Acme's Foobar 1.0 Installation [1]" />

    <Directory Id='TARGETDIR' Name='SourceDir'>
      <Directory Id='ProgramFilesFolder' Name='PFiles'>
        <Directory Id='Acme' Name='Acme'>
          <Directory Id="APPLICATIONFOLDER"  Name='Foobar 1.0'>
            <Component Id='MainExecutable'
Guid='10205233-A761-41E4-950B-213C91187383'>
              <File Id='FoobarEXE' Name='FoobarAppl10.exe' DiskId='1'
Source='FoobarAppl10.exe' KeyPath='yes'>
              </File>
            </Component>
          </Directory>
        </Directory>
      </Directory>
      <Directory Id="DesktopFolder" Name="Desktop" />
    </Directory>

    <Feature Id='Complete' Level='1' Title='MyCo' Description='The complete
package.' >
            <ComponentRef Id='MainExecutable' />
    </Feature>

    <UIRef Id="WixUI_Advanced" />

    <Property Id="ApplicationFolderName" Value="My Program" />
    <Property Id="WixAppFolder" Value="WixPerMachineFolder" />
    <Property Id='ALLUSERS' Value='2' />
    <Property Id='MSIINSTALLPERUSER' Value='1' />

  </Product>
</Wix>