Program: 40293
Project: 40293
Buggy source:
public void handleKeyCode(int keyCode){
switch (keyCode) {
case Keyboard.KEY_LSHIFT:
case Keyboard.KEY_RSHIFT:
case Keyboard.KEY_LCONTROL:
case Keyboard.KEY_RCONTROL:
case Keyboard.KEY_LMETA:
case Keyboard.KEY_RMETA:
case Keyboard.KEY_LMENU:
case Keyboard.KEY_RMENU:
case Keyboard.KEY_F2:
case Keyboard.KEY_ESCAPE:
    break;
case Keyboard.KEY_BACK:
  if (atStart()) {
    return;
  }
if (hungryBackspace && ix - owner.getTabSize() >= 0) {
  String cut=owner.getLine(iy).substring(ix - owner.getTabSize(),ix);
  if (cut.length() == owner.getTabSize() && cut.trim().length() == 0) {
    for (int i=0; i < owner.getTabSize(); i++) {
      owner.backspace(this);
    }
  }
 else {
    setLast();
    owner.backspace(this);
  }
}
 else {
  setLast();
  owner.backspace(this);
}
break;
case Keyboard.KEY_LEFT:
setLast();
move(ix > 0 ? -1 : 0,0);
break;
case Keyboard.KEY_RIGHT:
setLast();
move(ix < getCurrentLine().length() ? 1 : 0,0);
break;
case Keyboard.KEY_DELETE:
owner.delete(ix,iy);
break;
case Keyboard.KEY_LBRACKET:
char openingBracket=Keyboard.getEventCharacter();
owner.place(openingBracket,ix,iy);
move(1,0);
if (matchBraces) {
owner.place((char)((int)(openingBracket + 2)),ix,iy);
}
break;
case Keyboard.KEY_UP:
if (iy > 0) {
int prevLineLen=getLineOffsetBy(-1).length();
move(ix >= prevLineLen ? prevLineLen - ix : 0,-1);
}
break;
case Keyboard.KEY_DOWN:
if (atEndOfLine() && iy < owner.getLineCount() - 1) {
move(getLineOffsetBy(1).length() - ix,1);
}
 else if (iy < owner.getLineCount() - 1) {
int nextLineLen=getLineOffsetBy(1).length();
move(ix >= nextLineLen ? nextLineLen - ix : 0,1);
}
break;
case Keyboard.KEY_HOME:
move(ix > 0 ? -ix : 0,0);
break;
case Keyboard.KEY_END:
moveToEnd();
break;
case Keyboard.KEY_RETURN:
owner.newline(ix,iy);
move(-ix,1);
carriageReturn();
break;
case Keyboard.KEY_TAB:
move(owner.tab(ix,iy),0);
break;
default :
owner.place(Keyboard.getEventCharacter(),ix,iy);
move(1,0);
break;
}
}

Fixed version (ground truth):
public void handleKeyCode(int keyCode){
switch (keyCode) {
case Keyboard.KEY_LSHIFT:
case Keyboard.KEY_RSHIFT:
case Keyboard.KEY_LCONTROL:
case Keyboard.KEY_RCONTROL:
case Keyboard.KEY_LMETA:
case Keyboard.KEY_RMETA:
case Keyboard.KEY_LMENU:
case Keyboard.KEY_RMENU:
case Keyboard.KEY_F2:
case Keyboard.KEY_ESCAPE:
    break;
case Keyboard.KEY_BACK:
  if (atStart()) {
    return;
  }
if (hungryBackspace && ix - owner.getTabSize() >= 0) {
  String cut=owner.getLine(iy).substring(ix - owner.getTabSize(),ix);
  if (cut.length() == owner.getTabSize() && cut.trim().length() == 0) {
    for (int i=0; i < owner.getTabSize(); i++) {
      owner.backspace(this);
    }
  }
 else {
    setLast();
    owner.backspace(this);
  }
}
 else {
  setLast();
  owner.backspace(this);
}
break;
case Keyboard.KEY_LEFT:
setLast();
move(ix > 0 ? -1 : 0,0);
break;
case Keyboard.KEY_RIGHT:
setLast();
move(ix < getCurrentLine().length() ? 1 : 0,0);
break;
case Keyboard.KEY_DELETE:
owner.delete(ix,iy);
break;
case Keyboard.KEY_LBRACKET:
char openingBracket=Keyboard.getEventCharacter();
owner.place(openingBracket,ix,iy);
move(1,0);
System.out.println(matchBraces);
if (matchBraces) {
owner.place((char)((int)(openingBracket + 2)),ix,iy);
}
break;
case Keyboard.KEY_UP:
if (iy > 0) {
int prevLineLen=getLineOffsetBy(-1).length();
move(ix >= prevLineLen ? prevLineLen - ix : 0,-1);
}
break;
case Keyboard.KEY_DOWN:
if (atEndOfLine() && iy < owner.getLineCount() - 1) {
move(getLineOffsetBy(1).length() - ix,1);
}
 else if (iy < owner.getLineCount() - 1) {
int nextLineLen=getLineOffsetBy(1).length();
move(ix >= nextLineLen ? nextLineLen - ix : 0,1);
}
break;
case Keyboard.KEY_HOME:
move(ix > 0 ? -ix : 0,0);
break;
case Keyboard.KEY_END:
moveToEnd();
break;
case Keyboard.KEY_RETURN:
owner.newline(ix,iy);
move(-ix,1);
carriageReturn();
break;
case Keyboard.KEY_TAB:
move(owner.tab(ix,iy),0);
break;
default :
owner.place(Keyboard.getEventCharacter(),ix,iy);
move(1,0);
break;
}
}