Volume mesh optimisation hangs

Hello! I experienced that Netgen hangs at the end of the "Optimise volume" meshing step.

To reproduce the issue with the attached mesh mesh.vol.gz :

1. Run Netgen and load the mesh above
2. In Mesh -> Meshing options, set "First Step" to "Optimize Volume" and "Print Messages" to "Most"; Apply changes
3. Click "Generate Mesh"

The mesh optimisation runs, apparently in its entirety, and at some point hangs, in the sense that the progress bar in the lower right corner of the Netgen window does not complete, but CPU usage drops to zero. Trying to generate another mesh results in an error message saying that a meshing operation is already in progress. The last bit of output produced reads

 Total badness = 1.75648e+06
 Total badness = 1.75617e+06
 SwapImprove 
 8154 swaps performed
 SwapImprove2 
 0 swaps performed
 ImproveMesh
 Total badness = 1.75102e+06
 Total badness = 1.74554e+06

I am using Netgen 6.2-dev, compiled from source.

Thanks for any help! Massimiliano

I edited the original message attaching a much smaller mesh that makes it easier to reproduce the issue.

Should be fixed in current master, sorry for the long response time.

Thanks! And no worries :)