NegativeArraySize Exception in Designer Editing Transformation

Encountered a NegativeArraySizeException editing a transformation for a virtual table.

To reproduce:

1. Import 2 BQT sources
2. Add a virtual model
3. Add a base table to the virtual model
4. Add smalla as transformation sources to the virtual table
5. Highlight and delete all columns in the SQL (all values between SELECT and FROM)
6. The NegativeArraySizeException is caused