WebIDE with XML Views: StackedColumn default aggregation

Hi,

I have sometimes trouble with XML Views. A lot controls need a default aggregation, but its hard to find it (any links?)

For example, i <l:Grid></:lGrid> needs a <l:content></content> before you can place content in it. (xmlns:l="sap.ui.layout")

Now i got the same trouble with sap.viz.ui5 controls.

Here my Example:

Namespaces

xmlns:viz="sap.viz"

xmlns:types="sap.viz.ui5.types"

xmlns:data="sap.viz.ui5.data"

StackedColumn control:

            <viz:ui5.StackedColumn id="StackedColumn" width="400px" height="600px">

                <viz:title>

                    <types:Title visible="true" text="Tickets"/>

                </viz:title>

                <viz:axis>

                    <types:Axis name="xAxis">

                        <types:Axis_title visible="true"/>

                        <types:Axis_lable hideSubLevels="true"/>

                    </types:Axis>

                    <types:Axis name="yAxis">

                        <types:Axis_title visible="true"/>

                        <types:Axis_lable visible="false"/>

                    </types:Axis>

                </viz:axis>

                <viz:dataset> 

                    <data:FlattenedDataset>

                         <viz:dimensions>

                            <data:DimensionDefinition axis="1" name="Days" value="{Days}"/>

                        </viz:dimensions>

                        <viz:measures>

                            <data:MeasureDefinition name="Critical Tickets" value="{Ticket_Crit}"/>

                            <data:MeasureDefinition name="None-Critical Tickets" value="{Ticket_None_Crit}"/>

                        </viz:measures>

                    </data:FlattenedDataset>

                </viz:dataset>   

            </viz:ui5.StackedColumn>

What I tried:

<viz:content></viz:content>

<viz:ui5.content></viz:ui5.content>

Also i tried to remove all <viz:title>, <viz:axis> and <viz:dataset>  tags.

All i get is this Error: Uncaught Error: Cannot add direct child without default aggregation defined for control sap.viz.ui5.StackedColumn

Thanks for any clue.

Dominique