I tried using ctrl +shift. But that didn't work for me. I have a work around.
Just created a text object and copy the expression from the gauge chart to the text object. The text object should now display the guage results.
Now drag the text object to the gauge chart and change the background color this code:= argb(35,255,255,255) this is the same color as the gauge chart. set the transparant mode now to 100%
I know this is not the quickest way, but it works for me.
If some else has a better idea, feel free to share it.