Fourth

Fourth

For cases like this, you can right-click on the modal spinner and then press "Inspect" (or "Q"), which displays the developer tools showing you the code for that element. In this case, the class of the modal spinner is "mp-spinner-overlay", so you can use the Stylus extension to remove it from the web page:

.mp-spinner-overlay {
  display: none;
}

This permanently resolves the problem for Monoprice. It's good for modals that break interaction, but also popups like newsletter signup forms, "Sign in with Google/Facebook/etc", and so on.