Angela Merkel was known to text during parliamentary sessions, sometimes with multiple phones, with colleagues about the ongoing debate.
Other anecdota: Nowadays it is only part of Green Party folklore from the past, but to knit in political sessions was a common sight. What is not so silly but just stupid is conservative delegates watching football during a sex work debate (2018, https://twitter.com/BoehmeMarco/status/1012001444302598146). In German Bundestag, parliamentary rules forbid to photograph "personal documents" (including phones and tablets) in a way that the content is recognizable.