Squared Squared

I accidentally noticed some unexpected behavior from the “gcalctool” calculator included with Ubuntu 10.10. It has a “squared” button, and if I push it twice:

rather than returning the value to the fourth power (which agrees with either interpretation of associativity), it actually computes the value to the 22nd power:

Which means the calculator is capable of computing any exponent as long as its decimal representation is all 2’s.