link: http://www.tip.it/runescape/?page=firemaking_calc.htm

 

Somehow, I can't check the Fire beacon item boxes (gloves and ring). It just shows a white square and is not clickable.

It's to do with you're current xp.

They only become available to click when you have the required level; afterall applying them before you have the level they require would give false results.

 

Both work fine for me unless I am viewing the "f2p" or "dungeoneering" lists; but that is correct as they are not usable in these cases.

Indeed. If you cannot select these two things in a situation where you should be able to use them (that is, using a valid category and having a sufficiently high FM level), please post what browser you are using. Otherwise, the calculator is working as intended.

 

Edit: user did not respond. I couldn't find any bugs in any browsers. Marking this as done.