Crash: Streamline Cut Tool + Undo

Phew, this is a tough one, because it's hard to reproduce, but if you know how, you can reliably crash NVil. NVil produces a fatal error, when trying to undo while the streamline engine Cut tool is active, but only under certain circumstances.

In the streamline tool, 'Context Cut(break edges)' is set to On Activated, I believe this is the default. I changed the hotkey to strg+X, but we do not necessarily need the shortcut to crash. If you want to use the shortcut for crashing, enable the option "Allow Tapped To Stay Live".

Make sure you have nothing selected and are in some component mode. Activate the tool, either through tapping the shortcut or from the tool search or radial menu. Start the cut by clicking on a component, release the mousebutton and then drag a cut line over several edges. Click on a vertex, release the mousebutton, drag the cut line over at least one edge, now hit your undo shortcut. You should get a nice fatal error. If Nvil simply doesn't want to crash, do the cut exactly like in the picture below.

Fixed.