filter editor 5

Once added the effect parameters appear at the bottom,

and the filter chain structure at the top.
By default the flood fill is set to solid black. 

Remember it won't take action unless you tick in 

the checkbox at the filter list on the left!

After applied, a black rectangle should be rendered. 

It is slightly larger than the object's previous bounding box.

For reference, go to the ”Filter General Settings” tab.

svg source