Uninstall of wix installer seems to do a repair instead of uninstalling - wix

Question

I have a project which uses wix to generate an install package. The install works fine, but when one tries to uninstall the project, everything looks nice - but after the unistall finishes the product ist still there (still functioning). The entry in add/remove programs disappears when uninstalled from there, but comes back after a refresh (F5). Testers have found that everything looks like the uninstall actually does a repair.
What are we doing wrong (the project otherwise only generates further component fragment files with "heat" (with HeatDirectory-Entries in the wixproj), and defines a few preprocessor variables)?
Here's the product.wxs. Sorry, I know thats a lot of code, but I do not know what I can safely omit to find the problem...:
<?xml version="1.0" encoding="UTF-8"?>
<?define ProductVersion=1.1.0.0?>
<?define UpgradeCode=$(var.UpdateCode)?>
<?define ProductName=$(var.PV) Name?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
<Product Id="*" Name="$(var.ProductName)" Language="1033" Version="$(var.ProductVersion)" Manufacturer="xyz" UpgradeCode="$(var.UpgradeCode)">
<Package InstallerVersion="200" Compressed="yes" InstallScope="perMachine" InstallPrivileges="elevated" />
<SetProperty Id="REINSTALL" Value="ALL" After="FindRelatedProducts" >Installed AND Remove<>"ALL"</SetProperty>
<SetProperty Id="REINSTALLMODE" Value="vamus" After="FindRelatedProducts">Installed AND Remove<>"ALL"</SetProperty>
<MajorUpgrade DowngradeErrorMessage="A newer version of $(var.ProductName) is already installed." />
<MediaTemplate EmbedCab="yes" />
<Feature Id="ProductFeature" Title="XY Installer" Level="1" ConfigurableDirectory="INSTALLLOCATION">
<ComponentGroupRef Id="ProductComponents" />
<ComponentGroupRef Id="DesktopShortcutComponentGroup"/>
<ComponentGroupRef Id="StartmenuShortcuts"/>
</Feature>
<CustomAction Id="RestoreDatabase" Directory="INSTALLLOCATION" ExeCommand="[INSTALLLOCATION]initial_db\BURestore.exe $(var.Sport)_$(var.Project) D:\$(var.Sport)\initial_db\db.bak" Execute="deferred" Return="ignore" HideTarget="no" Impersonate="no" />
<CustomAction Id="RenameFormatFilesFolder" Directory="LISTTOOLLOCATION" ExeCommand="cmd /c "mv FormatFiles fmt"" Return="ignore" Impersonate="yes"></CustomAction>
<InstallExecuteSequence>
<Custom Action="RestoreDatabase" Before="InstallFinalize">NOT REMOVE</Custom>
<Custom Action="RenameFormatFilesFolder" After="InstallFinalize">NOT REMOVE</Custom>
</InstallExecuteSequence>
<Property Id="WIXUI_INSTALLDIR" Value="INSTALLLOCATION"/>
<UI>
<UIRef Id="WixUI_InstallDir"/>
<Publish Dialog="WelcomeDlg" Control="Next" Event="NewDialog" Value="InstallDirDlg" Order="2">1</Publish>
<Publish Dialog="InstallDirDlg" Control="Back" Event="NewDialog" Value="WelcomeDlg" Order="2">1</Publish>
</UI>
</Product>
<Fragment>
<Directory Id="TARGETDIR" Name="SourceDir">
<Directory Id="ROOTDIR" Name="D"/>
<Directory Id="INSTALLLOCATION" Name="$(var.PV)">
<Directory Id="CONF" Name="conf">
<Directory Id="LISTTOOLLOCATION" Name="PRINT"></Directory>
</Directory>
</Directory>
<Directory Id="DesktopFolder" />
<Directory Id="ProgramMenuFolder">
<Directory Id="ProgramMenuSubfolder" Name="ST">
<Directory Id="ApplicationFolder" Name="$(var.ProductName)" />
</Directory>
</Directory>
</Directory>
</Fragment>
<Fragment>
<ComponentGroup Id="ProductComponents" Directory="INSTALLLOCATION">
<ComponentGroupRef Id="RootFiles" />
<ComponentGroupRef Id="ListToolFiles" />
<ComponentGroupRef Id="inis" />
</ComponentGroup>
<ComponentGroup Id="DesktopShortcutComponentGroup">
<Component Id="DesktopShortcutComponent" Guid="{C54B....}" Directory="DesktopFolder">
<Shortcut Id="ApplicationDesktopShortcut"
Name="$(var.ProductName)"
Description="$(var.ProductName) Application"
Target="[INSTALLLOCATION]RO.exe"
WorkingDirectory="INSTALLLOCATION"/>
<RemoveFolder Id="DesktopFolder" On="uninstall"/>
<RegistryValue Root="HKCU" Key="Software\ST\$(var.ProductName)" Name="installed" Type="integer" Value="1" KeyPath="yes"/>
</Component>
</ComponentGroup>
<ComponentGroup Id="StartmenuShortcuts" Directory="ApplicationFolder">
<Component Id="StartmenuShortcutComp" Guid="{ACD9...}">
<Shortcut Id="StartmenuShortcut" Name="$(var.ProductName)" Description="$(var.ProductName) Application" Target="[INSTALLLOCATION]RO.exe" WorkingDirectory="INSTALLLOCATION" />
<Shortcut Id="UninstallProduct" Name="Uninstall $(var.ProductName)" Target="[SystemFolder]msiexec.exe" Arguments="/x [ProductCode]" Description="Uninstalls $(var.ProductName)" />
<RemoveFolder Id="RemoveProgramMenuSubfolder" Directory="ProgramMenuSubfolder" On="uninstall"/>
<RemoveFolder Id="RemoveApplicationFolder" Directory="ApplicationFolder" On="uninstall"/>
<RegistryValue Root="HKCU" Key="Software\ST\$(var.ProductName)" Name="installed" Type="integer" Value="1" KeyPath="yes"/>
</Component>
</ComponentGroup>
</Fragment>
</Wix>

Answer 1

The below two lines are making this issue.
<SetProperty Id="REINSTALL" Value="ALL" After="FindRelatedProducts" >Installed AND Remove<>"ALL"</SetProperty>
<SetProperty Id="REINSTALLMODE" Value="vamus" After="FindRelatedProducts">Installed AND Remove<>"ALL"</SetProperty>
That condition become true because Remove will be set ALL in Uninstall after InstallValidate action in Install execute sequence. Please check below link for more details.
https://msdn.microsoft.com/en-us/library/aa368013(v=vs.85).aspx