Returning new nodes on import doesn't work through eto window

Working off of this solution Import 3dm or stl and return new nodes - #2 by dale

I tried calling this from a button in a Eto.Forms.Dialog window.

When I query for the serial number it is the same from the time I open the UI, to close it. However if I call this directly, it works fine. Is there something that blocks this workflow from a UI?

Interestingly, on a mac this works great, I only notice the issue on Windows.