Radar and EW is a game of cat and mouse. The EW is only as good as the surprise it prepares for the radar technology and operators. Then they find a way to cope with it till a new EW method is invented. The is why EW and counter-EW capabilities are one of the best kept secrets in the arsenal and are very restricted in their usage in training to keep them as such.
btw, this is why I seriously believe radar guided missiles are way overrated. They are not useless, but not very high kill probability either. The IAF had a bad experience with them due to EW counter measures. Missiles improved, but so did the EW which is kept as a surprise.
The "windows" were just the first move in the game. Jamming spoofing and decoy methods were all developed used in WWII.