The trigger editor gets random crashes or I get a message about an invalid pointer or similar in tesh.dll?
The syntax highlighter has problems with Window Blinds and maybe other window mods. Set an exception for the World Editor in Window Blinds or disable the tool while you're using NewGen. To add an exception open WindowBlinds -> settings tab -> change the look of an app -> add per application setting. There tell it to completly ignore NewGen. I believe that it's sufficient to add JassNewGenPack\bin\exehack.exe there but you might also have to add Warcraft III\worldedit.exe and/or Warcraft III\worldedit121.exe to fix the error.