If the browser has a zoomlevel (prolly for any pixelDeviceRatio != 1) the element resizing in client.ts does not yield the same values as FitAddon.fit leading to additional resize adjustments done by the fit addon (see #4112 (comment)). This prolly also happens in the opposite direction for shrinking and a zoomlevel <100% (not tested though).

We might want to fix that, so ppl dont c&p faulty code resulting in nonsense resize events with poor performance in the end.

(@Tyriar - you might want to test if something similar happens in vscode, if the pixelDeviceRatio is not perfectly 1).