It’s not an extjs issue! You click on the gear icon in the right bottom corner and uncheck Log XMLHttpRequests.
more recent (Chrome 55): open the console, right click the open area, uncheck “Log XMLHttpRequests”. OR click the vertical “…” in the top right, go to settings, and uncheck “Log XMLHttpRequests” under the “Console” header.
recent screenshot:
older screenshot:
even older screenshot:
