Custom Bootstrapper with Transparent wpf window

[j-hn]

I had a custom boostrapper with a WPF UI in wix 3.14. which was ok.
I converted this to wix 4, and eventually got it running, (following the examples)
however.... my main wpf window has AllowsTransparency="true" this causes the install to fail, If I set it to false it then installs fine.
it worked fine in wix 3.x.
any way I can get may transparency back?

Thanks

Inner Exception 1:
InvalidOperationException: Cannot change AllowsTransparency after a Window has been shown or WindowInteropHelper.EnsureHandle has been called.

[nirbar]

I'm running a BA that has AllowsTransparency="true" without any error.
Did you make sure that you're not calling EnsureHandle before InitializeComponent in RootView c'tor?

[j-hn]

Oh Blimey! I'm an idiot!

thanks for your help