When you use a LineStyleListener , you shouldn't use the following API calls:
getStyleRangeAtOffset(int offset)
StyleRange[] getStyleRanges()
void replaceStyleRanges(int start, int length, StyleRange[] ranges)
void setStyleRange(StyleRange range)
void setStyleRanges(StyleRange[] ranges)
Mixing these API calls with a LineStyleListener is unsupported.
(The Definitive Guide to SWT and JFace
by Robert Harris and Rob Warner
Apress 2004
)