Child PHP edits not being picked up
I have started a child theme to start making edits to the parent theme. While the CSS child won't change without adding !important tage in the code, I guess I can live with that for now. The problem now is that i cant get the PHP file edits to override the parent theme. Almost at the point where I am going to scrap Jobroller as a bad joke. I'm only looking to edit some of the text on the page at the moment. Not looking to mess about with functions. My question is this, does anyone know how to get PHP child theme edits to override the parent theme? I'm sure that I am not the only one that has asked this question in the past. But I have searched and have not found a sensible, or clear, answer. I am astounded that this fundamental piece of information doesn't seem to be included in the documentation for Jobroller.
Any help would be appreciated.
The example that I would like to change is the text on the "submit a job" button that is located in the "sidebar-sjob.php" file nested in the "includes" folder.