Be careful with old versions!
These versions are displayed for reference and testing purposes. You should always use the latest version of an add-on.
Justin Watt made a extended version "Resizeable Form Fields", but because i work on a completely different solution, to get rid of the flaws of 0.1a, i will not support development based on the old code.
This add-on is not compatible with your version of Firefox because of the following: