Julian Eisel
b9e54566e3
Code to check if the Outliner tree-element type was the general ID one would always check against "0" (explicity or even implicitly). For somebody unfamiliar with the code this is very confusing. Instead the value should be given a name, e.g. through an enum. Adds `TSE_SOME_ID` as the "default" ID tree-element type. Other types may still represent IDs, as I explained in a comment at the definition. There may also still be cases where the type is checked against "0". I noted in the comment that such cases should be cleaned up if found.