t.click doesn't seem to be working too well. Does that control have to be visible in the DOM window in order to push a button? It appears to be failing because it can't find the "center". t.click doesn't fire when I close the DOM window either.
Line: 22194
el = this.elementFromPoint(center[0], center[1]);
el is null??
center[0]: = 548
center[1]: = 392
Support Forum
This behaviour tends to be different across browsers, in IE it needs to be visible for sure, in Chrome - not. Can you post more details (a test case ideally)?.
Read the API documentation