We've improved the performance of the directory sidebar when many files are created or deleted. This has resulted in a 10x speed improvement!
Previously the directory sidebar was re-rendered each time a file was created or deleted. This would cause the web page to become slow or unresponsive when there were many files in the directory sidebar, since it could mean re-rendering it hundreds or even thousands of times.
We've optimized it so that now so that when many files are created or deleted at once, only one re-render is necessary.