Update- this issue was solved, updated code is at the end of the post.

I am trying to create a swimmer plot to visualize individual patient duration of treatment with a drug administered at multiple dose levels (DLs). Each patient will be be assigned to treatment with only one DL, but multiple patients can be assigned to a given DL (e.g. 3 patients at DL1, 3 patients and DL2, etc.). I would like to color code the bars in the swimmer plot according to DL.

I am using the swimplot package for R and have been following the guide located here (