How to type a circumflex
Hold the a and choose 6 from the popup menu to get â
Hold the e and choose 6 from the popup menu to get ê
Type ^ (Shift-6) followed by an a result â
Type ^ (Shift 6) followed by an e result ê
So ^e gives ê
This also works for several other characters.
See the 'accent settings' in the Holdkey program.