Plugin not displaying in WordPress admin area

This might be a great plugin if you could see it, but after installing it in WordPress it is not properly visible in the WordPress admin area. The code fix for this is very simple – one CSS style change to the iframe it uses – but it doesn’t inspire great confidence in the plugin or Paywhirl in general to have such a basic and massive error that would take less than 1 minute to fix.

https://ww.wp.xz.cn/plugins/paywhirl-recurring-payments/