Note entry with the keyboard: In the very first capella versions, notation one octave higher could be done with both shift keys. For several years, however, you have now been able to choose via Extras-Options...-Note Entry:
A hint from the user guide: Windows encounters problems with distinguishing the two shift keys. After program start, often the first click of the right shift key is interpreted as the left one. To prevent this from happening, shortly click the left shift key after program start.