instance_id for new objects in rooms is incorrect if there are gaps.

[sorlok]

Steps to reproduce:

1. Create a new project. Create 1 room and 1 object.
2. Create 10 instances of the object in the room.
3. Delete (right-click) instances 7,8,9.
4. Save, close the editor.
5. Re-open the editor and the project.
6. Create 4 instances of the object in the room. You will now have two instances with the same ID (the 10th object).

Any ideas?

[egofree71]

One way to fix this problem is to call 'Defrags Ids' menu ('Resources->Defrag Ids').

[sorlok]

This is a good short-term fix, thanks. But I think we need to fix this at the editor level too; it's no fun having two instances with the same id (one will just silently overwrite the other).

[RobertBColton]

This ticket is an extension of #188 and we will get it resolved @sorlok

[RobertBColton]

@sorlok If you do not mind I am going to close this actually because it is a duplicate of #82 but I think I may fix it in this next LGM release I am going to make within the next few months. I am linking the ticket still because you have the steps to reproduce it. It should be easy to fix, but we don't need two tickets.

[RobertBColton]

This was finally corrected in 1.8.7 by properly reading and writing the instance names in the GMX format. I was only able to reproduce sorlok's issue with the GMX file handlers. I also discovered that I was not updating the lastId properly which caused the issue.

LateralGM/org/lateralgm/file/GMXFileReader.java

Line 1873 in 3d51e5d

// NOTE: Because LGM still supports GMK, we attempt to preserve the ID which Studio