A known problem that is fixed in newer versions.Andre Klapperak-47@gmx.net
Creative Commons Share Alike 3.0
Message fonts are not the same fonts as in other applications
In version 3.0 it can happen that EditPreferencesMail PreferencesGeneralMessage FontsUse the same fonts as other applications is enabled but Evolution still uses different fonts than other parts of the system.
This bug is fixed from Evolution version 3.0.3 (stable series) and 3.1.4 (unstable development series) onwards. If this is not the case, please add a comment to the corresponding bug report. Note that from version 3.2 onwards this setting is located under EditPreferencesMail PreferencesGeneralMessage DisplayUse the same fonts as other applications.