We have another new version of Logisim to play with.  You can use it on the instructional machines by typing:
         java -jar ~cs61c/bin/logisim-v20b4.jar

or you can snag it for home use from the Logisim Website.  When submitting bug reports in the future, please be sure to indicate what version of the software you found the problem in.

I'll repost here a message from Dr. Burch that can be found on the Logisim Website:

To the students of UC/Berkeley's CS61C: Thank you for your feedback and bug reports! With Beta 3 and Beta 4, I've responsed to the more reproducible bugs as well as some of the low-hanging feature suggestions. Other important comments were excluded only because addressing them would delay these releases; I hope they'll come in future versions. Continued feedback through your course page is valuable and appreciated!

The list of changes in this version follows:

• Bug fix: A subcircuit nested within a larger circuit could not be moved.
• Bug fix: Changing a subcircuit pin's width could lead to freezing when opening a supercircuit already containing it.
• Bug fix: Switching the attribute set displayed while an attribute's combo box was open could lead to endless exceptions.
• Feature: Input and output pins are now visually distinct (output pins are circles/rounded rectangles). Constants' appearance was also changed to allow for rounded output pins.
• Feature: Most attributes, including pin and gate bit widths, are editable after a component is created. The remaining exceptions are gate size, the number of gate inputs, and the main splitter attributes.