Logisim’s “Analyse Circuit” function doesn’t work with multi-bit inputs.
What can I do?
The “Analyse Circuit” function works with single-bit inputs/outputs only.
You can either change your design to work with multiple single-bit inputs/outputs, or generate the truth table manually using the poke tool.
Using multiple single-bit inputs to replace a multi-bit input is okay for the purpose of testing, but we highly recommend against using it in the final version of your designs.