Apologies if reported earlier, did a search on this but could not find. Four accounts - three POP3, one NNTP. Fourth account POP3 just added. Unable to add recipient into address field - same applies to "CC" "BCC". Alpha input not recognised. Deleted fourth account - same result. Address field shows message usual pop up message to "use Tab to auto complete" even though no alpha input in field - selection comes up, clicking on same does not populate "To" field. Interesting if I input say "a' in address field (which does not print in field) all the correct selections in the address book appear. When selecting "reply" the address field is briefly populated, then blanks out. Again same issues as above. Double clicking on address in address book has no effect; this option is selected in "Settings". Bug, feature, or me?
Fiddled for a while. Killed the Synaptics touch pad - that seem to resolve the issue. BRF!