333 bytes, text/xul
I'm using the M17 binary from the ftp site build 2000080712. When I specify an onresize event handler, nothing happens when I resize the window. Attaching an test case now. Stick it in the navigator/content directory and run it with mozilla -console -chrome chrome://navigator/content/resize.xul Try resizing the window. Expected: alert pops up. What happens: Nothing.
This is very similar to bug 960, but that relates to onresize in the html, not the xul. It is fixed.
*** This bug has been marked as a duplicate of 45244 ***