Debugger internals, use re "debug", memory usage

If yes, could you peek in your JavaScript console window for any errors? That's Tools -> JavaScript Console. It's probably shock-full off jitter from pages you have visited, but scroll to the bottom (or just select the "Clear" menu entry to flush out all the old messages), then in your main browser window, run the bookmarklet on the page you have open, and see if you get anything that resembles a useful error message in the console window.