closing STL opened from session file gives traceback

[Elaine Meng]

After restoring the attached session (just one STL model), command "close" gives traceback:
Traceback (most recent call last):
File "/Users/meng/Desktop/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/chimera/cmd_line/gui.py", line 121, in on_enter
cmd.execute()
File "/Users/meng/Desktop/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/chimera/core/commands/cli.py", line 1780, in execute
results.append(ci.function(session, kw_args))
File "/Users/meng/Desktop/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/chimera/core/commands/close.py", line 16, in close
m.close(models)
File "/Users/meng/Desktop/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/chimera/core/models.py", line 246, in close
m.delete()
File "/Users/meng/Desktop/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/chimera/core/models.py", line 52, in delete
delattr(self, "session")
AttributeError: session

[Greg Couch]

Model wasn't getting session attribute restored. Reworked code to emphasis how restoring needs to initialize objects.

[Elaine Meng]

Now I can close the STL opened from a session without traceback, thanks!

The display is not redrawn, however (looks like the structure is still there after it was closed) until you try to reposition it with the mouse. Don't know if it is a related bugette or something else.

[Eric Pettersen]

Opening the out-of-sync redraw problem as a separate ticket