@xHeaven collapse should not happen from left to right. the whole point of collapse is to give more room for content. the side bar collapses towards left. allow more room for content in the middle.
Commit
c531fac
I also noticed that pressing Enter on collapse / expand causes the keyboard focus to be lost, which looks like a bug.
Does it still happen? Can you tell me how we can reproduce it?
Still reproducible after hard reload:
$('button[data-test="nav-collapse-button"]').focus();
$('button[data-test="nav-collapse-button"]').click();
console.log(document.activeElement); // <body>
commit c531fac