can I control where the UI appears on the post-editor screen?

try dragging the box by its title bar

Thanks for the reply! First, that’s not working — probably a sign of how old the plugin code is. Second, i want it in an established place for all the current and future editors of the site, so if I could just get it to, on first viewing, show up where I want it, that’s the preferred functionality.

If you’ve got any other thoughts, that’d be great. Thanks again.

if you cannot rearrange the position of metaboxes, there may be a plugin issue. Try dragging one of the metaboxes after deactivating all plugins. If it works, reactivate them one-by-one & retest until you find which plugin caused the problem. Then you would have an indication of what would need to be fixed. It may or may not be your custom plugin causing this.

Again, to be clear, I have no interest in drag-and-drop capability, just in sticking the darn box where I want it via the plugin’s native state. Thanks anyway for the advice.

If you’ve got any links to plugin writing articles or support that deal with how to determine where on the post-editing page the plugin’s stuff shows up, that would be awesome! Thanks.

If the ability to drag & drop metaboxes is not working, it indicates that something is broken. If that problem was addressed, you should be able to position the metaboxes exactly as you wish without any further coding.

Documentation on adding metaboxes is at: https://codex.www.ads-software.com/Function_Reference/add_meta_box the $context & $priority parameters determine where the meta boxes appear.

The tutorial at https://wp.smashingmagazine.com/2011/10/04/create-custom-post-meta-boxes-wordpress/ may help

Thanks again — great reference links, I appreciate it!