hotspot [X] should close the pop up window
Just a little bit of feedback for your consideration:
When the user clicks an incorrect hotspot and the response bubble pops up, the point of interaction is marked with a red X in a light red circle. This looks like an interactive element, in fact, it is similar to the "close window" X that appears in the top right corner of the box responding to a correct answer.
What I am finding is my students are clicking the X (to no effect) rather than the refresh icon to try again.
Rather than changing this red cross for another icon, a simple solution might be to simply make it function as anticipated (do the same thing as the refresh/reload icon). What do you think?