[LDCad] Strange behaviour part usage countdown

[Fredrik Hareide]

I am finding the behaviour for part usage countdown a bit strange.

If I build an official model where I have several submodels and I isolate one of the models it suddenly forgets that the parts are used in one of the other submodels.

In my opinion the countdown should be on global level in the file. Not per submodel.

Just ask if it didn't make sense