100% fill required for first layer

[GrumpyDave]

Hello,I am trying to print a small pegboard hook on my Anycubic Kobra using Prusa Slicer 2.5.0 and am finding that I need a 100% infill on that layer. As can be seen by the picture this is not occurring but I cannot seem to find a setting to instruct the slicer to do this.