Hi Martin, I'm sorry I'm still not entirely sure if I understand you correctly.

> Switch off 'Display hidden lines' and switch on 'Hidden edges on selected only'.
> Then, when selected, only the hidden wireframe edges of parts would be visible
> and snap-able, <....>

Ok, so you're saying that when "Display hidden lines" was turned off, there would still be some hidden edge display being shown? If so then that's problematic that the setting would seem to say that no hidden lines would be shown yet you are talking about showing some...

I think it's pretty important to be able to turn off the hidden line display entirely, that's what happens with the first "Display hidden lines" checkbox being on or off. There is also a shortcut for that under the View palette. It's useful to be able to totally turn off the hidden line display in just one spot because if you have some hidden lines cluttering up your display it lets you definitely clear them all by going to just one control and clicking it.

That's why the new "hidden edges on selected only" only modifies how edges are displayed _if_ hidden edge display is enabled, it allows you to still totally disable all hidden lines by using the other "Display hidden lines" checkbox the same as before.

Hopefully the new option for also controlling the hidden-line display of edges only on selected objects will help to manage them in some situations without needing to do a full on or off, but I think it's still a good idea to have a sort of master on/off switch still though.

- Michael