Test wall thickness

I use a program slicer Cura
When printing thin walled models (boxes , forms, cookies, etc.):
1) the slicer is not properly fills the space inside the walls.
Depending on the parameters of the "Wall Thikness" and "Infill Density" appear inside the voids, which should not be.
2) Also if the option "Wall Thikness", less than 2 times the wall thickness, then the inner filling is made diagonally at an angle of 45 to the line of the wall. And with a small wall thickness vibration. I think i