Bug in loading external color sheet

[sulheim]

This works well if I import the txt file before I load any other data. However, if I load the graphics after I've loaded the edges. layers and nodes, I get the following error message:

Warning: Error in $<-.data.frame: replacement has 0 rows, data has 1255
  91: stop
  90: $<-.data.frame
  76: observeEventHandler [C:\Users\username\Documents\muxviz\muxViz-master/server.R#8434]
   5: runApp