ENIGMA Development Environment

But also, this doesn't make sense, because renaming a resource in the tree does not do any sorting?

I did more tests. I think it's not directly related to tree editing, but to some change in the focus between Lateralgm and its plugin. If the plugin is not loaded, you don't have this error.

In the error message, you can see :

   at sun.swing.SwingUtilities2.compositeRequestFocus(SwingUtilities2.java:1556)

And in order to have this focus Swing uses internally some arrays sorting. I've tested also Enigma with Kubuntu, and you have also this error ! It seems very likely that this error will happen with every distribution with KDE installed. I don't know how Swing works internally, but i guess depending on the OS and its graphics layer, some rendering and functionalities are not always working in the same way, even if in theory the result should be always the same.
The only possible fix i've found so far is adding in LateralGm:

System.setProperty("java.util.Arrays.useLegacyMergeSort", "true");

What about using font_add_sprite ? :

http://enigma-dev.org/docs/Wiki/Font_add_sprite

Adds a new font from the given sprite with the sub images mapped to the characters.

Perhaps it could be a workaround for your problem ?

This seems to me be perfect Runes fonts ! What's the problem ?    

http://en.wikipedia.org/wiki/Runes

Ok, a couple of things.

1) XNA, BlitzBasic, DarkBasic are all proprietary.
2) BlitzBasic, DarkBasic, and XNA are not very modern.
3) XNA is C#......

Not very modern ? Do you know when C++ was created ? 1983 ! Very modern indeed !  (Hey, Robert i am just teasing you !  )
More seriously, i was talking about these tools and languages not to say we should imitate them, but to see what type of tools are available and to understand why GM is so successful.
As you said you don't care about the compatibility of GM, i was wondering if it's really necessary to make a new games engine. It seems that there is already a lot of excellent games engines existing, but very often they don't come with an optimized IDE for games. What about making instead a new IDE for one/or several existing game engines. Just thinking...

I did more tests. First i tried on a virtual machine Linux Mint 16 KDE 32 bits with the oracle version of Java 32 bits. Same error. Then i tried Linux Cinnamon 32 bits and it didn't have this problem. Is this related to KDE ? I don't know, but i searched for the error message, and i've found this:

http://bugs.java.com/bugdatabase/view_bug.do?bug_id=7075600

and also:

It seems to me like you've hit a bug in the JDK since the error seems to come from Swing classes.

Options:

Define the property  java.util.Arrays.useLegacyMergeSort as true. Either using in your code the line

System.setProperty("java.util.Arrays.useLegacyMergeSort", "true");
before any Swing code. As the first line in the main method should work.

Or adding

-Djava.util.Arrays.useLegacyMergeSort=true
to your starting options (in the console, or in the project properties in an IDE, Ant script, etc.)

Upgrade your JDK and see if the problem goes away

Downgrade to Java 6

http://stackoverflow.com/questions/13575224/comparison-method-violates-its-general-contract-timsort-and-gridlayout

It seems this error happens only on some systems with Java >= 7. So in LGM.java i added in the main method the following line :

public static void main(final String[] args)
{

....
   
System.setProperty("java.util.Arrays.useLegacyMergeSort", "true");
And i don't have anymore this error ! 

Robert, as i don't know yet git very well, could you do for me a pull request with this line ?  Thanks in advance !

Update:
It seems Sort algorithm has changed since Java 7 :

Area: API: Utilities
Synopsis: Updated sort behavior for Arrays and Collections may throw an IllegalArgumentException
Description: The sorting algorithm used by java.util.Arrays.sort and (indirectly) by java.util.Collections.sort has been replaced. The new sort implementation may throw an IllegalArgumentException if it detects a Comparable that violates the Comparable contract. The previous implementation silently ignored such a situation.
If the previous behavior is desired, you can use the new system property, java.util.Arrays.useLegacyMergeSort, to restore previous mergesort behavior.
Nature of Incompatibility: behavioral
RFE: 6804124

http://www.oracle.com/technetwork/java/javase/compatibility-417013.html

Sort algorithm changes in Java 7:

http://dertompson.com/2012/11/23/sort-algorithm-changes-in-java-7/

Concerning new ideas for your project : i think the features which are missing the most are in the IDE. The rooms editor for instance sucks. It doesn't any advanced functions to modify a group of objects or an undo method. Concerning the code editor, there is no global search. All modern IDE should have a global search function.

Same could be said about the ENIGMA project. Why use ENIGMA over GM:S?

Because it's open-source and free.