Nope, no issue with that either.
I've put it in the table header, above the table, below the table, below the table and a HTML block, inside a container below the table and a HTML block, etc. Works just as expected.
If you find that it doesn't work in certain position, it could be:
- There's another element with the same id.
- There's JS/JQuery just above it that has an error, hence rendering the JS/JQuery after it invalid.
That's a few reasons I could think of for now. If you really want I can have a look at your form to figure out why it isn't working.
Edit: I've found the only thing that stops it working is if there is
another form on the same page above it. I think this is due to Max's JS code which looks up the <form> tag when clicking the select all checkbox, hence only the first form gets selected.
Shouldn't be a difficult thing to fix, but Max seems to have a lot of things on his plate at the moment. In the meantime, you'll have to do a quick JQuery coding to do the select all. If you google it you should be able to create the function yourself.