I believe I have found a bug with the Toolbar widget. If I disable a button in the Toolbar, it is greyed out and clicking on the button does nothing. However, if the window is resized and the button is moved to the overflow section (the hamburger menu), it will appear greyed out, but clicking on it will fire the associated click event handler.
I am using the Q3 2014 SP2 release of Kendo, and I see this behavior in Chrome as well as Internet Explorer 11. You can see the behavior here: http://dojo.telerik.com/iSajA/3
. Run the sample, and click the "Click Me" button when it is visible in the main toolbar - the click handler will not fire. However, when you resize the window to force "Click Me" to the overflow menu, the click event will fire, even though the button is disabled.
Please let me know if there is a workaround, or if a fix will be coming for this.