Hi, i'm trying the following code and keep getting an error. If i change the FormLayout for then FlowLayout.

It show "com.google.gwt.core.client.JavaScriptException: (Error): Invalid HTML source for this operation." on the console (only when i use FormLayout), i've already googled for it i found a few topics saying it was an issue on I.E. Not on my case though. I'll include the full StackTrace at the bottom.

Any help would realy be appreciated.
Thanks.

Code:
//tab manager
TabPanel tabs = new TabPanel();  
tabs.setDeferredRender(false); 
tabs.setWidth(400);


//tab
TabItem personal = new TabItem();  
personal.setText( clientMasterDetailField.getLabel() );  
personal.setWidth(200);
personal.setHeight(200);


FormPanel panel = new FormPanel();
panel.setFrame(true);  
panel.setIconStyle("icon-form");  
panel.setCollapsible(true);  
panel.setHeading("FormPanel");  
panel.setSize(470, -1);  
//if i change this for FlowLayout, works just fine
panel.setLayout(new FlowLayout());    

NumberField clientField = new NumberField();

panel.add( clientField );
panel.setSize(340, 180);

personal.add(panel);

tabs.add(personal);
Code:
com.google.gwt.core.client.JavaScriptException: (Error): Invalid HTML source for this operation.
 number: -2146827687
 description: Fonte de HTML inválida para esta operação.
 at com.extjs.gxt.ui.client.core.Template.appendInternal(Native Method)
 at com.extjs.gxt.ui.client.core.Template.insert(Template.java:165)
 at com.extjs.gxt.ui.client.widget.layout.FormLayout.renderField(FormLayout.java:313)
 at com.extjs.gxt.ui.client.widget.layout.FormLayout.renderComponent(FormLayout.java:277)
 at com.extjs.gxt.ui.client.widget.Layout.renderAll(Layout.java:248)
 at com.extjs.gxt.ui.client.widget.Layout.onLayout(Layout.java:228)
 at com.extjs.gxt.ui.client.widget.layout.AnchorLayout.onLayout(AnchorLayout.java:73)
 at com.extjs.gxt.ui.client.widget.Layout.layout(Layout.java:93)
 at com.extjs.gxt.ui.client.widget.Layout.onResize(Layout.java:239)
 at com.extjs.gxt.ui.client.widget.Layout$1.handleEvent(Layout.java:52)
 at com.extjs.gxt.ui.client.widget.Layout$1.handleEvent(Layout.java:1)
 at com.extjs.gxt.ui.client.event.BaseObservable.fireEvent(BaseObservable.java:74)
 at com.extjs.gxt.ui.client.widget.Component.fireEvent(Component.java:443)
 at com.extjs.gxt.ui.client.widget.BoxComponent.setSize(BoxComponent.java:500)
 at com.extjs.gxt.ui.client.widget.BoxComponent.afterRender(BoxComponent.java:548)
 at com.extjs.gxt.ui.client.widget.ScrollContainer.afterRender(ScrollContainer.java:194)
 at com.extjs.gxt.ui.client.widget.ContentPanel.afterRender(ContentPanel.java:741)
 at com.extjs.gxt.ui.client.widget.Component.render(Component.java:918)
 at com.extjs.gxt.ui.client.widget.Layout.renderComponent(Layout.java:257)
 at com.extjs.gxt.ui.client.widget.layout.FlowLayout.renderComponent(FlowLayout.java:117)
 at com.extjs.gxt.ui.client.widget.Layout.renderAll(Layout.java:248)
 at com.extjs.gxt.ui.client.widget.Layout.onLayout(Layout.java:228)
 at com.extjs.gxt.ui.client.widget.layout.FlowLayout.onLayout(FlowLayout.java:109)
 at com.extjs.gxt.ui.client.widget.Layout.layout(Layout.java:93)
 at com.extjs.gxt.ui.client.widget.Container.doLayout(Container.java:360)
 at com.extjs.gxt.ui.client.widget.Container.layout(Container.java:455)
 at com.extjs.gxt.ui.client.widget.LayoutContainer.layout(LayoutContainer.java:238)
 at com.extjs.gxt.ui.client.widget.Container.doLayout(Container.java:376)
 at com.extjs.gxt.ui.client.widget.Container.layout(Container.java:455)
 at com.extjs.gxt.ui.client.widget.Layout.layoutContainer(Layout.java:223)
 at com.extjs.gxt.ui.client.widget.layout.CardLayout.setActiveItem(CardLayout.java:76)
 at com.extjs.gxt.ui.client.widget.TabPanel.setSelection(TabPanel.java:609)
 at com.extjs.gxt.ui.client.widget.TabPanel.onAttach(TabPanel.java:699)
 at com.extjs.gxt.ui.client.widget.ComponentHelper.doAttach(ComponentHelper.java:24)
 at com.extjs.gxt.ui.client.widget.Container.doLayout(Container.java:365)
 at com.extjs.gxt.ui.client.widget.Container.layout(Container.java:455)
 at com.extjs.gxt.ui.client.widget.LayoutContainer.layout(LayoutContainer.java:238)
 at com.extjs.gxt.ui.client.widget.Container.doLayout(Container.java:376)
 at com.extjs.gxt.ui.client.widget.Container.layout(Container.java:455)
 at com.extjs.gxt.ui.client.widget.LayoutContainer.layout(LayoutContainer.java:238)
 at com.extjs.gxt.ui.client.widget.VerticalPanel.onRender(VerticalPanel.java:166)
 at com.extjs.gxt.ui.client.widget.Component.render(Component.java:851)
 at com.extjs.gxt.ui.client.widget.Layout.renderComponent(Layout.java:257)
 at com.extjs.gxt.ui.client.widget.layout.FlowLayout.renderComponent(FlowLayout.java:117)
 at com.extjs.gxt.ui.client.widget.Layout.renderAll(Layout.java:248)
 at com.extjs.gxt.ui.client.widget.Layout.onLayout(Layout.java:228)
 at com.extjs.gxt.ui.client.widget.layout.FlowLayout.onLayout(FlowLayout.java:109)
 at com.extjs.gxt.ui.client.widget.Layout.layout(Layout.java:93)
 at com.extjs.gxt.ui.client.widget.Container.doLayout(Container.java:360)
 at br.com.dyad.client.widget.ClientProcess.doLayout(ClientProcess.java:1221)
 at com.extjs.gxt.ui.client.widget.Container.layout(Container.java:455)
 at com.extjs.gxt.ui.client.widget.LayoutContainer.layout(LayoutContainer.java:238)
 at com.extjs.gxt.ui.client.widget.Window.layout(Window.java:530)
 at com.extjs.gxt.ui.client.widget.Window.afterShow(Window.java:872)
 at com.extjs.gxt.ui.client.widget.Window.show(Window.java:839)
 at br.com.dyad.client.widget.ClientObjectSincronizer$1.onSuccess(ClientObjectSincronizer.java:58)
 at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:215)
 at com.google.gwt.http.client.Request.fireOnResponseReceivedImpl(Request.java:254)
 at com.google.gwt.http.client.Request.fireOnResponseReceivedAndCatch(Request.java:226)
 at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:217)