Description of problem: I am using plain/text as default format for emails. The undo doesn't work well. For example. When I paste some text and undo, it will remove some other text. In combination with quoted text it causes disaster. Version-Release number of selected component (if applicable): 3.16.5-3.fc22 How reproducible: always.
Thanks for a bug report. This is discussed upstream, for example here [1]. There are many other Composer bug reports filled upstream. [1] https://bugzilla.gnome.org/show_bug.cgi?id=749712