How to remove splitter and keeping one ui element

I've got an approach to this which is similar to yours, but simpler.

1. Enable Layout editing mode
2. Right click the element you want to keep and select 'Copy'
3. Point the splitter separator (a double-pointed arrow should appear) and right click it (so that after you right click, both halves are highlighted; if only one gets highlighted, try right-clicking again) - you are selecting the whole splitter element this way - and select 'Paste'
4. Disable Layout editing mode

This is the simplest method I've found. The absence of a native way to remove one half of the splitter is really puzzling, but that's it.