Custom Ribbon Bold Button not enabled in runtime (1 Viewer)

Dear All,

I have added a custom ribbon buttons by adding following xml

<group id="format" label="Format">
<control idMso="Bold" enabled="true"/>
<control idMso="Italic" enabled="true"/>
<control idMso="Underline" enabled="true"/>
<control idMso="FontColorPicker" enabled="true"/>
<control idMso="FontFillBackColorPicker" enabled="true"/>
<control idMso="IndentIncrease" enabled="true"/>
<control idMso="IndentDecrease" enabled="true"/>
<control idMso="Bullets" enabled="true"/>
<control idMso="Numbering" enabled="true"/>
</group>

However, i want this to be enabled when report is in runtime. Unfortunately these buttons get disbaled automatically. I want them to be enabled all the time.