Quitting\restarting doesn't fix this, there appears to be no way to get rid of them. Even if I remove the model and reimport it, delete the process and create a new one, the supports still show up. I basically have to start everything from scratch to get rid of them. Did not have this issue in previous versions.
Repro steps:
* Import model that needs supports
* Via the Support Generation window, "Generate Automatic Supports"
* Slice the model, see the supports. Exit preview mode.
* Back in the 3d view, access the "Support Generation window again, and "Clear all supports"
* Slice the model: The supports are still there. Exit preview mode.
* Quit \ restart simplify 3d.
* Reslice the model: The supports are still there. Exit preview mode.
* Back in the 3d view, access the "Support Generation" window again. Manually add one support.
* Reslice the model: The single support shows up (and none of the old ones). Exit preview mode.
* Back in the 3d view, access the "Support Generation" window again. "Clear all supports".
* Reslice the model: All the old supports are back again. Exit preview mode.
* Delete the model, reimport it.
* Reslice the model: All the old supports are back again. Exit preview mode.
* Delete the process and add a new one.
* Reslice the model: All the old supports are back again.