WebKitCSSUtilImpl.setDelay method seems to cause com.google.gwt.core.client.JavaScriptException: (TypeError) occasionally

What steps will reproduce the problem?
Still have not discovered a pattern yet. Occasionally when I start my MGWT web 
application in my latest Chrome browser, I get a JavascriptException on the 
startup screen. The stacktrace seems to indicate that a MouseOutEvent is 
causing a call to WebKitCSSUtilImpl.setDelay with the Element parameter set to 
NULL.

Here is an excerpt of the StackTrace:
Caused by: com.google.gwt.core.client.JavaScriptException: (TypeError) 
@com.googlecode.mgwt.ui.client.util.impl.WebkitCssUtilImpl::setDelay(Lcom/google
/gwt/user/client/Element;I)([null, int: 300]): Cannot read property 'style' of 
null
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:249)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:571)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeVoid(ModuleSpace.java:299)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeVoid(JavaScriptHost.java:107)
    at com.googlecode.mgwt.ui.client.util.impl.WebkitCssUtilImpl.setDelay(WebkitCssUtilImpl.java)
    at com.googlecode.mgwt.ui.client.util.CssUtil.setTransitionsDelay(CssUtil.java:39)
    at com.googlecode.mgwt.ui.client.widget.impl.ScrollPanelTouchImpl.resetPos(ScrollPanelTouchImpl.java:923)
    at com.googlecode.mgwt.ui.client.widget.impl.ScrollPanelTouchImpl.end(ScrollPanelTouchImpl.java:830)
    at com.googlecode.mgwt.ui.client.widget.impl.ScrollPanelTouchImpl.mouseOut(ScrollPanelTouchImpl.java:1022)
    at com.googlecode.mgwt.ui.client.widget.impl.ScrollPanelTouchImpl.access$29(ScrollPanelTouchImpl.java:991)
    at com.googlecode.mgwt.ui.client.widget.impl.ScrollPanelTouchImpl$10.onMouseOut(ScrollPanelTouchImpl.java:1707)
    at com.google.gwt.event.dom.client.MouseOutEvent.dispatch(MouseOutEvent.java:66)
    at com.google.gwt.event.dom.client.MouseOutEvent.dispatch(MouseOutEvent.java:1)
    at com.google.gwt.event.shared.GwtEvent.dispatch(GwtEvent.java:1)
    at com.google.web.bindery.event.shared.EventBus.dispatchEvent(EventBus.java:40)
    at com.google.web.bindery.event.shared.SimpleEventBus.doFire(SimpleEventBus.java:193)
    at com.google.web.bindery.event.shared.SimpleEventBus.fireEvent(SimpleEventBus.java:88)
    at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:127)
    ... 80 more

What is the expected output? What do you see instead?
Ultimately the native JavaScript call should not happen when no Element can be 
associated to it. 

What version of the product are you using? On what operating system?
1.2.0-SNAPSHOT, Ubuntu 13.04

Full StackTrace and screenshot is attached.

Original issue reported on code.google.com by roman.ka...@gmail.com on 13 Oct 2013 at 11:04

Attachments:

viktorthang / mgwt

WebKitCSSUtilImpl.setDelay method seems to cause com.google.gwt.core.client.JavaScriptException: (TypeError) occasionally #311