I would like to add that there are some things that Dev.exe has trouble auto-updating, some examples I have found.
-research window locations (prerequisite arrows will redraw depending on where you relocate the techs)
-build menu icon locations (i.e. if you move ships around in the build menu - done by moving ships around in the player.entity file)
-meshes (sometimes editing hardpoints works, but I have found that the game usually needs to be reloaded)
-adding / removing researches, ships, structures from a player.entity file (these won't be visually removed until you restart the game)
Most of the above requires a game restart to see how things look after changes are made, things like particles, strings, research prerequisites, textures, ship stats, etc.... do a good job of auto-updating when changes are made.
My apologies if you already knew this and I am telling you something you already know