Invalid Mixing Target

For some strange reason, I am getting this “Invalid Mixing Target” error when I start up my project. The breakpoints hits on the 2nd if statement here at line 32 in webix_debug.js:

webix.assert_error = function(message){
	//jshint debug:true
	webix.log("error",message);
	if (webix.message && typeof message == "string")
		webix.message({ type:"debug", text:message, expire:-1 });
	if (webix.debug !== false)
		debugger;
};

Nevermind… I commented out some view code and I was still trying to attach a ProgressBar to that view.

Anyway try to explore the stack trace, as here is a standard breakpoint that hits in case any error is caught in the app.