When adding a canvas element i.e. <canvas id="MyCanvas"></canvas>
Passing in the ID: var ctx = document.getElementById("MyCanvas").getContext("2d");
This results in making the html document non-responsive in Chrome. All interaction within the Tab is ignored. You must close the tab and open a new one for the state change.
Not a high impact bug as it is easily avoided but the result is fairly non-graceful failure and certainly easy to do on accident.