Hey @Ngoci!
If you're locked out of editing an app you can try using the _historyOffset URL parameter to step back in time to a point when it didn't crash. Be careful with it though as it will cause you to permanently lose changes you've made when doing a revert. You can read more documentation on it here.
It may also help if we can take a look at screenshot of your browser console when the crash happens and any error messaging you might be seeing (though it sounds like it's just freezing at the moment?)