In that case I suggest you to keep using the current buggy editor...
Keep in mind that a software can´t have support of too old software, but we are talking about upgrade a browser that uses (in general) the same resources requirements that the old one
why? good browsers keep functionality....
i would suggest to use htm5, because it is going to be a standard and you don´t requiere to have a powerful pc, only an updated browser that supports it
lot of shareware apps show a comparison between the free ones... that´s how the market works..
but of course, if also you don´t know which are the "fantastic features" that your mod has...