I am currently trying to load a custom layout handle after the catalog_category_view handle through the use of an observer that looks for the event catalog_controller_category_init_after.
The layout handle works when removing blocks, however ignores any layout update that adds a block to the layout.
Am I using the correct event to load the handle? Is there a better way of loading the custom layout handle?
This is because catalog_controller_category_init_after is triggered before the layout is loaded. That means, if you add a layout handle in the observer for this event, it is the first one, before catalog_category_view, even before default. So any block you are referencing in your handle does not exist yet.
The <remove> tag works differently, it operates on the fully merged XML tree, that's why you can remove blocks. But instantiating blocks and executing actions happens in order of definition.
Use a different event. A good choice is controller_action_layout_render_before_catalog_category_view which is triggered immediately before the layout is rendered, so you can be sure that it has been fully loaded.
