Widget doesn't show in Panel - uibinder

Question

I'm using gxt 3.0.1 and gwt 2.5.1.
I’ve created FramedPanel and Widget with UiBinder and it works fine. Widget inherits from Composite. After adding Widget to FramedPanel it doesn't show up.
Before:
After:
Main View:
<ui:with type="com.sencha.gxt.core.client.util.Margins" field="centerMargins">
<ui:attributes top="4" right="4" bottom="0" left="4" />
</ui:with>
<ui:with type="com.sencha.gxt.widget.core.client.container.MarginData" field="centerData">
<ui:attributes margins="{centerMargins}" />
</ui:with>
<ui:with type="com.sencha.gxt.core.client.util.Margins" field="middleMargins">
<ui:attributes top="5" right="0" bottom="5" left="0" />
</ui:with>
<ui:with type="com.sencha.gxt.widget.core.client.container.VerticalLayoutContainer.VerticalLayoutData" field="middleData">
<ui:attributes margins="{middleMargins}" width="1" height="-1" />
</ui:with>
<ui:with type="com.sencha.gxt.widget.core.client.container.BorderLayoutContainer.BorderLayoutData" field="eastData">
<ui:attributes minSize="200" maxSize="1000" size="400" margins="{eastMargins}" collapsible="true" split="true" />
</ui:with>
<ui:with type="com.sencha.gxt.core.client.util.Margins" field="eastMargins">
<ui:attributes top="0" right="1" bottom="0" left="5" />
</ui:with>
<core:FramedPanel headerVisible="false">
<c:BorderLayoutContainer borders="false">
<c:center layoutData="{centerData}">
<c:VerticalLayoutContainer ui:field="mainVerContainer">
<c:child layoutData="{middleData}">
<p:PanView />
</c:child>
</c:VerticalLayoutContainer>
</c:center>
<c:east layoutData="{eastData}">
<core:ContentPanel headingText="" />
</c:east>
</c:BorderLayoutContainer>
</core:FramedPanel>
Widget's View:
<ui:with type="com.sencha.gxt.widget.core.client.grid.ColumnModel" field="columnModel" />
<ui:with type="com.sencha.gxt.data.shared.ListStore" field="store" />
<ui:with type="com.sencha.gxt.widget.core.client.grid.GridView" field="view">
<ui:attributes stripeRows="true" columnLines="true" />
</ui:with>
<ui:with type="com.sencha.gxt.widget.core.client.container.MarginData" field="centerData">
<ui:attributes margins="{centerMargins}" />
</ui:with>
<ui:with type="com.sencha.gxt.core.client.util.Margins" field="centerMargins">
<ui:attributes top="0" right="0" bottom="0" left="0" />
</ui:with>
<ui:with type="com.sencha.gxt.widget.core.client.container.VerticalLayoutContainer.VerticalLayoutData" field="topData">
<ui:attributes width="1" height="30" />
</ui:with>
<ui:with type="com.sencha.gxt.widget.core.client.container.VerticalLayoutContainer.VerticalLayoutData" field="middleData">
<ui:attributes width="1" height="1" />
</ui:with>
<ui:with type="com.sencha.gxt.core.client.util.Margins" field="southMargins">
<ui:attributes top="1" right="1" bottom="5" left="1" />
</ui:with>
<ui:with type="com.sencha.gxt.widget.core.client.container.BorderLayoutContainer.BorderLayoutData" field="southData">
<ui:attributes size=".5f" minSize="200" maxSize="1000" margins="{southMargins}" collapsible="true" split="true" />
</ui:with>
<core:ContentPanel headerVisible="false" ui:field="mainPanel" borders="false">
<c:BorderLayoutContainer borders="false">
<c:center layoutData="{centerData}">
<core:ContentPanel headingText="Grid" collapsible="false" ui:field="documentPanel">
<c:VerticalLayoutContainer borders="false">
<c:child layoutData="{topData}">
<t:ToolBar ui:field="topToolBar">
<b:TextButton ui:field="toPreviousPackageButton" toolTip="Up" />
<t:SeparatorToolItem />
</t:ToolBar>
</c:child>
<c:child layoutData="{middleData}">
<grid:Grid cm="{columnModel}" store="{store}" view="{view}" loadMask="true" columnReordering="true" borders="false" />
</c:child>
</c:VerticalLayoutContainer>
</core:ContentPanel>
</c:center>
<c:south layoutData="{southData}">
<core:ContentPanel ui:field="propertiesPanel" headingText="Properties" />
</c:south>
</c:BorderLayoutContainer>
</core:ContentPanel>