implement robuster version of setDocumentListener() + add test for it
add test class for StyleImpl
add test for getStyleRange()
add test for resetToNormal()
add test for setBoldOn()
add dummy test for setFaintOn()
add a test for setItalicOn()
add a test for setUnderlineSingle()
improve implementation of setImageNegative() and add test
add test for setCrossedOut()
add test for setBoldOrFaintOff()
JBIDE-16949: Active runtime radio button should be checked
add test for setItalicOff()
add test for setUnderlineNone()
add test for setImagePositive()
add test for setNotCrossedOut()