QTDragon HD spindle incrementally increase/decrease speed

The documentation located here indicates the following:

To have the manual spindle buttons also incrementally increase/decrease speed:
#action_spindle_fwd{
qproperty-spindle_up_action: true;
}
#action_spindle_rev{
qproperty-spindle_down_action: true;
}

Is this correct?
I've not been able to find a file where this (#action_spindle_fwd) is located?
If it doesn't exist is there a specific file or block that I should add it to in order to get this functionality working?

I did find this entity in the qtdragon_hd.ui file:
<item>
<widget class="ActionButton" name="action_spindle_fwd">
.....
</item>

Is this where it should be added?
 

from the docs:
linuxcnc.org/docs/devel/html/gui/qtdragon.html#_stylesheets

press F12 an editor will show for the style sheet:
 

press the 'copy to edit tab' and then edit as you please.
apply to test.
Then save for next time. The view tab should show the path/filename of the stylesheet that qtdragon will use.
 

Thanks Chris!

As an FYI I tried this and it doesn't allow the spindle to increase or decrease. 

hmm seems to work in my tests now.

It doesn't work for me by using the mouse. Were you using the keyboard?

No clicking the screen button with a mouse.