The editor in 5.5 appears to be very buggy, at least on current Windows versions.
It improved a little bit when I enabled Windows 10 compatibility mode, but not much. Sometimes it seems to crash, when just clicking on it. Forget about clicking on most of the menu options.
I'm not sure if it was released in this state (5.5 was a beta version after all, wasn't it?), or it was simply introduced when Windows was updated several times since it was released. 5.5 has a copyright date of 1998 in its About screen... It's unfortunate, as it had some interesting ideas.
The version 6 editor is more stable, but still has issues: the well known by now 100% CPU load, of at least one CPU core, all the time. And I still get an error occasionally when starting the editor, that a file with a strange filename cannot be found. I have not written large programs with it, but it generally seemed to work fine for smaller ones.
The V6 editor was written in TB itself, by John R. Arscott. I bet it must be one of the larger programs out there that was written in True BASIC. He has not been on the forum for some time now, hope he is doing well.
The good news is that you can use your own text editor and run/compile your programs with TBSystem.exe, but strangely this is not documented clearly AFAIK. I would suggest the TB folks to add an article on the website for this. This could be a viable option, if you don't want your CPU to become hot and could extend the lifetime of version 6 a bit longer IMO. I would gladly contribute an article on this, if @admin would be interested.
TL;DR I would recommend staying on version 6.