If you experience any problems, such as checkboxes disappearing in the settings screen, it is likely that the JavaScript cache is having an adverse effect.
Please refer to this person’s article for more details, and try force reload.
For users of paid and free templates
If you are using a paid or free template, the template creator may have done something to the JavaScript and CSS.
A particularly common process is to hide the version information below, which is also a security measure for WordPress.
When the above process takes place, the old information remains in the browser’s cache, so it often happens that the screen is in a strange state even after updating the QA heatmap plugin.
In this case, please try to force reload your browser.