Looks like we can't reproduce the issue or there's a problem in the test case provided.
Warning - Chrome Canary dev tools (28.0.1487.0) seems to break some Sencha events
Its a bug but I don't think it is a Sencha issue. I've wasted half a day on it, so figured I'd warn others. I've sent a bug report to the Chrome developers.
Summary: Opening the latest Chrome Canary dev tools stops the 'tap' event from firing.
Get Canary (28.0.1487.0)
Go to the Sencha touch kitchen sink demo:
Click around - look for the "tap" event in the events panel.
Open dev tools.
Click around some more - *for me*, the tap event has gone.
As I said, I think it could be a Chrome bug, but don't know the framework well enough to be sure.
Yes, this looks to be a browser issue. Chrome is known to break things in their beta and more experimental browsers.
I'm using 27.0.1453.116, so your mileage may vary, but if I turn off the "Emulate touch events" settings in Dev Tools > Settings > Overrides, tap events are working for me.