Previously angular was re-rendering the entire queue whenever any downloads changed their state. The websocket provides progress updates at a high frequency, which combined with a long download queue can quickly cause hundreds of thousands of dom nodes to be created. This results in a spike in memory usage which may persist for some time depending on browser behaviour.
Adding a trackBy function resolves the issue by telling angular which row relates to a particular download.
The arguments passed to retryDownload by the retry button do not match what the function actually expects. This causes downloads to break if a custom folder is set and also causes some settings like format and custom name prefix to be ignored.
James Lyne