In IE, yes. I work with an exceptionally complex ext.js application (not develop, I'm just a user of it). In IE you can click a button, make a cup of tea, an

In IE, yes. I work with an exceptionally complex ext.js application (not develop, I'm just a user of it). In IE you can click a button, make a cup of tea, and come back to see it finish working. In Chrome and Firefox, there's nothing wrong with the performance of the client.