For all ideas create a new issue. If it is approved go ahead and write it. Remember that you idea may not be approved so do not start writting it immediately.
For all bugs create a new issue. In each report please state your browser version, how to reproduce the bug, and explain what the bug is. If you have an idea of what is going wrong that would be very helpful. If you want to fix the bug submit a pull request!
Thanks for contributing!