I have a small problem with the lib feat part, the first tab related to the configuration is always grayed out, the second the display of sketches when I insert the function in my room the turquoise sketch is displayed but the red dot is hidden.
1/ I can't reproduce your problem on the configuration part, can you take a screenshot?
2/ From your description I guess a reference problem when importing your .sldlfp into a room.
When inserting SW asks you to fill in the references that allowed the creation of the different functions you want to import, in this case to create your plan on which the addition of material is based:
A tangent face --> the face of the cube deformed by the "bending" function (note that you won't be able to use this .sldlfp for planar faces)
A reference point to "snap" the plan, which is made by the 3D sketch
In the pictures you will find the procedure for insertion.
In summary:
When inserting a .sldlfp, you must always make sure to have similar reference elements in the part file, in this case 1 point and 1 tangent face