Multilevel-Dimension leads to set-identifier being converted to number

[pepperblue]

If I have a dataset with Multilevel-Dimension on rows and set-identifiers that can be converted to numbers ("6+", "6++"):

I get the following chart (with set-identifiers converted to numbers):

Changing Line 1237 in "plugin.js" (function "process_data") from:
parseFloat(args.data.cellset[row][col].value.replace(/[^a-zA-Z 0-9.]+/g,'')) && col>0)
to:
parseFloat(args.data.cellset[row][col].value.replace(/[^a-zA-Z 0-9.]+/g,'')) && col>lowest_level)
... things are working as expected