In some cases the string values in the XML attributes are not colored with the expected color, but default to black.

 

This was reproduced when there is only single quotation mark on visible on the line. And also if the count of the visible quotation marks on the line is an odd number (not always reproducible). 

Or "!====" wont' be commented in custom language if "!" is the commenting symbol.

The issue resides in the word splitting function in WordTaggerBase class.