This is a long standing Microsoft technique
They've done this for many years. Cause a problem for a competitive product and let the problem stand just long enough to give the competitor a bad reputation. Then fix the problem without notice and imply it never existed.
Opera is, I'm sure, very aware of this, and has taken strong publicity countermeasures early enough to be effective
Microsoft will target Opera very strongly because it is currently the leading browser for the enhanced mobile phone market, a huge market Microsoft dearly wants to dominate.
[link|http://www.aaxnet.com|AAx]