Sometimes when we’re making a theme we have to deal with some of the known “quirks” of WordPress, these may manifest themselves in several different ways within your theme or plugin and may appear as bugs etc. In reality most Developers are well aware of some of the limitations of WordPress as a system, but often new users are unaware of this and see these things as bugs.
I’m going to use this article to list off some of the quirks I know of, hopefully this will help out a few people running into the same issue and help you to work around / with this. I will update this article periodically.
1. Checkboxes in the WP Customiser can sometimes refuse to save.
This is definitely a weird one, but has a simple fix, rather than making a choice and saving just once, do the same a few times, check, save, uncheck save etc. This will “force” the option and will work fine forever from there. You may need to exit and re-enter the options panel.
2. Options saved as Arrays now require all items to be changed. (Users of MyFolio, TheArchitect, TheGrid)
In some of my older themes we saved options as arrays, traditionally this meant a small theme options change was required to load everything into the database, this is no longer the case. What you should do now is change each option away from its default state, save options, then return them all to default & save. All options will then propagate properly.