Hello,

If I am not mistaken, this can be done. You would need to set Content properties with your text. Then change DisplayMode properties to Content.

Regards
Handy 

Well I want both image and text to always display not only as tooltip.

As far as I have tried this does not work

Hello,

You would need to use DisplayMode properties into ContentAndImage. 
At first, Maybe you would not notice the text. The text is overriden by the images. 
You would need to customize your ImageWidth and ImageHeight properties.
Please change the NaN value into some certain value.
e.g

<Intersoft:UXDockButton d:LayoutOverrides="Width, Height" Icon="BitComet.png" DisplayMode="ContentAndImage" Content="Comet" ImageHeight="50" ImageWidth="50" VerticalContentAlignment="Center" HorizontalContentAlignment="Center" ImageLoaderTextVisibility="Visible" />

Regards,
Handy