widget titles not displaying

I would like the widget titles to display in the sidebar of my blog page but they don’t (e.g. ‘Recent Posts’ title is not displayed over the recent posts, and ‘Recent Comments’ is not over the comments and so on). I am wondering if this could be related to having the Hide Title plugin installed. However, the problem still exists after deactivating and then still after deleting the plugin. Can having installed it leave permanent code changes that would cause the problem to persist after deleting the plugin?

I did find these comments in the Hide Title FAQ:

Hey! This plugin is hiding things I don’t want hidden!

By default this plugin looks for the .entry-title class and hides it. If it doesn’t find it it will look for any h1 or h2 elements that contain the title and hide them instead. To change the default .entry-title selector to something that makes more sense to you, add the following code to the functions.php file of your current theme:

global $DojoDigitalHideTitle;
// Be sure to replace “.your-selector” with your selector!
$DojoDigitalHideTitle->set_selector(‘.your-selector’);

As noted in the comments, you’ll need to replace the string .your-selector with the css selector you’d like hidden. It can be any valid css selector such as h1, .myclass, #myid, etc. I recommend using a class or id to avoid accidentally hiding unforeseen elements.

https://wordpress.org/plugins/hide-title/