We have contact and company as the deafult logging obejcts, when writing emails. Users can decide to log the correspondance on deals as well but found it hard to find the right deal to log the email on, since the naming is different across our company and depending on the user writing the email, he or she do the search of a deal differently. So my suggestion is, as an admin, to define what other properties than the name should be included in the overview of deals associated to the contact.
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