Hi there, I have never used this, but I imagine Plus! sends the value to your option according to <Range> [For example, 50% of 0-255 would be 128]
xml code:
<Control xsi:type="SliderControl" Id="SliderTest">
<Position Top="5" Width="120" Left="5"/>
<Help>Use an option that accepts numerical values</Help>
<Attributes>
<AutoTicks>0</AutoTicks>
<EnableSelRange>false</EnableSelRange>
<Orientation>Horizontal</Orientation>
<TickMarks>Bottom</TickMarks>
</Attributes>
<Range>
<Minimum>0</Minimum>
<Maximum>255</Maximum>
</Range>
</Control>