4959 (Export SVG menu) hangs pcbnew permanently!

I'm testing BZR-4959

This error is critical.

To reproduce the error:
I click to menu File -> Export SVG.

At that point you can generate the SVG file or simply do nothing.
Try to close the the Dialog window, IT'S NOT POSSIBLE.
so the PCBnew, of course.

I suggest to save every work in PCBNew before each one wants to generate the SVG files.

After than "CTRL-ALT-CANC" or "kill" cmd is the only way to close the process.

The bug doesn't affect the BZR-4955 version.

thanks,
Callisto.