I had another thought, but without seeing the code, I’m not sure if this could be the problem. There are different commands when pressing the mouse that interact differently. Depending on what she is using, switching from MouseDown to MouseWentDown might also solve the problem.
This is a great post that helps explain the difference. It refers to keys, but the same applies to the mouse. keyDown VS. keyWentDown
Can the student try some of the solutions suggested and see how they work?
Let me know if any of those solutions work or if you have any more questions. Thanks for all you do to help your student be successful. ~Cecilia