Correctly implement IsDefault.
Correctly implement IsDefault.

When only the scale or pan was changed, this was causing the changes to
be lost after pressing Ok.

Fenex/Pinta,Fenex/Pinta,Mailaender/Pinta,PintaProject/Pinta,Mailaender/Pinta,PintaProject/Pinta,PintaProject/Pinta,jakeclawson/Pinta,jakeclawson/Pinta