2D labels 'frames' problem: local variable 'bg2' referenced before assignment

[goddard@…]

The following bug report has been submitted:
Platform:        Darwin-18.7.0-x86_64-i386-64bit
ChimeraX Version: 0.91 (2019-08-06)
Description
2dlabel change frames argument is broken.

Log:
UCSF ChimeraX version: 0.91 (2019-08-06)  
© 2016-2019 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> open 1a0m format mmCIF fromDatabase pdb

1a0m title:  
1.1 angstrom crystal structure of A-conotoxin [TYR15]-epi [more info...]  
  
Chain information for 1a0m #1  
---  
Chain | Description  
A B | α-conotoxin [TYR15]-epi  
  
Non-standard residues in 1a0m #1  
---  
NH2 — amino group  
  
  

> 2dlabels create l1 text Test color blue

> 2dlabels change l1 color yellow frames 100

Traceback (most recent call last):  
File "/Users/goddard/Desktop/ChimeraX Aug 6
2019.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/cmd_line/tool.py", line 254, in execute  
cmd.run(cmd_text)  
File "/Users/goddard/Desktop/ChimeraX Aug 6
2019.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/core/commands/cli.py", line 2655, in run  
result = ci.function(session, **kw_args)  
File "/Users/goddard/Desktop/ChimeraX Aug 6
2019.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/label/label2d.py", line 100, in label_change  
_InterpolateLabel(session, l, color, bg_color, size, xpos, ypos, visibility,
margin, outline, frames)  
File "/Users/goddard/Desktop/ChimeraX Aug 6
2019.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/label/label2d.py", line 121, in __init__  
self.color2 = bg2  
UnboundLocalError: local variable 'bg2' referenced before assignment  
  
UnboundLocalError: local variable 'bg2' referenced before assignment  
  
File "/Users/goddard/Desktop/ChimeraX Aug 6
2019.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/label/label2d.py", line 121, in __init__  
self.color2 = bg2  
  
See log for complete Python traceback.  
  




OpenGL version: 4.1 ATI-2.11.20
OpenGL renderer: AMD Radeon Pro 580 OpenGL Engine
OpenGL vendor: ATI Technologies Inc.