And the award for mostest dumbest person 2012 goes to: ME. And here's a fix that actually works (tested on WinXP/32 and Win7/64) (you can revert r3738):
200 public void createWindow(DrawableLWJGL drawable, DisplayMode mode, Canvas parent, int x, int y) throws LWJGLException {
201 close_requested = false;
202 is_dirty = false;
203 isMinimized = false;
204 isFocused = false;
205 did_maximize = false;
206 this.parent = parent;
207 hasParent = parent != null;
208 long parent_hwnd = parent != null ? getHwnd(parent) : 0;
209 this.hwnd = nCreateWindow(x, y, mode.getWidth(), mode.getHeight(), Display.isFullscreen() || isUndecorated(), parent != null, parent_hwnd);
///////////////////////////////////////
//the window is created non-resizable by default. it will be made resizable after showing it, if needed
this.resizable=false;
///////////////////////////////////////
210 if (hwnd == 0) {
211 throw new LWJGLException("Failed to create window");
Sorry for wasting your time, Matzon.
Cheers,
Simon