Bond rotation mouse mode broken

[Tom Goddard]

Using bond rotation mouse mode gives the following error in current daily build on Mac.

Traceback (most recent call last):

File "/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/ui/mousemodes.py", line 374, in <lambda>

gw.mouseMoveEvent = lambda e, s=self: s._dispatch_mouse_event(e, "mouse_drag")

File "/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/ui/mousemodes.py", line 314, in _dispatch_mouse_event

f(MouseEvent(event))

File "/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/bond_rot/mouse_rot.py", line 32, in mouse_drag

br.angle += dy

File "/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/chimerax/bond_rot/bond_rot.py", line 80, in set_angle

moving, fixed = self.moving_side.coord, self.bond.other_atom(self.moving_side).coord

AttributeError: 'BondRotater' object has no attribute 'bond'

AttributeError: 'BondRotater' object has no attribute 'bond'