During the ‘export’ to a .obj file format, the dialog showing the “Fewer Polygons … More Polygons” slider is improperly sized - the buttons to accept/proceed or cancel are not visible. The dialog works correctly as an “Enter” keystroke proceeds to perform the export.
This ought to be fixed in the most recent WIP release. It was broken for a release or two. Have you updated to WIP 5A693?
I thought I updated yesterday, but the build number was 5A683. Verified that this is fixed in 5A693!