form_for("item[subobject]", @item) do |f|
This would produce a radio button with an ID="item[subobject]_title",
which is invalid because IDs can't include bracket characters. All
other form_helpers already fixed this issue using the "sanitize_name"
function, but this one omitted to use it.
I provide a patch with a unit test case and a fix in this ticket:
The dev.rubyonrails.org says for my patch to get integrated I should
post here asking people to mark my ticket +1.
So I'm posting!