Initial displayport seems to be set to the viewport somewhere using a different code path. It is not oversized for the first paint. This causes the unpleasant delay as soon as I pan around during page load. We have to oversize that first displayport too.
Created attachment 644803 [details] [diff] [review] Temporary hack, we will need to revisit this This needs to be fixed properly by setting the displayport to a larger area than just the viewport but before the page has already been loaded. This patch will mask it to look decent once the page has finished loading and before panning.