If this Govt falls and there are fresh elections, then the benefit is likely to be for the Congress and that is the reason for them to keep away from the JD(S) now. Besides, they probably have had enough of handling Deve Gowda, who is behaving like a PM of the JD(S). The dignity of being a former PM is lost on this person.
The JD(S) and BJP combine, having got a chance at power in Karnataka, should not rock the boat now. For, they may not get such a chance once again should they fretter it away now. Hope sense will prevail. Otherwise both these parties will be loosers.