new to dose comparison module

Operating system: windows
Slicer version: 4.11
Expected behavior:
Actual behavior:

Just downloaded 3D slicer today - I am wanting to compare dose distributions via gamma analysis using the Dose Comparison module. I am able to generate the image of the gamma analysis with the color wash representing the gamma values and I get the % of points that meet the Gamma criteria. I am having trouble displaying the scale and potentially manipulating the displayed gamma distribution color wash. Also, is there an easy way within 3D slicer to display the histogram of the Gamma values?