With the help of justenuf2bdangerous, I think I have finally found a solution to the problem.
"Seamless Tabbing" has to be set to false. Even though in Captivate 7 there's a checkbox for seamless tabbing and it's unchecked by default, apparently it's not off in the code. Apparently there is a bug in Captivate 7. The workaround is to edit the SCORM-utilities.js javascript file (in the published zip file) and change the following line of code:
so.addParam("seamlesstabbing","config.seamlesstabbing") to so.addParam("seamlesstabbing","false")