All,
Maybe as a newbie I have missed some configurable EA parameters (in this case I'd warmly acknowledge pointers on how to fix any of the items below) but it rather seems to me that there are some minor gotchas in EA's (6.5) behavior when editing sequence diagrams, mostly related to fragments (specifically loop). Did not test it with EA 7.0 but none of the items below is listed on the fixed-issue list. Positive aspect: the behavior is reproducible.

1. When selecting a bigger font for objects (e.g. 14), the loop condition text (in square brackets) does not preserve the distance to the loop fragment name tab (i.e., the condition text's upper part overlaps the loop tab in the upper left fragment corner). Bugfix required, as feature request you could file a user-configurable font size and gap for fragment conditions.
2. (Loop?) fragments can not be moved by the Z-ordering, i.e., they stay on top, regardless of the Z order. This is annoying when selecting a solid color fill for the loop fragment as this color covers the object lifelines. Imho the missing Z-ordering makes solid color fill for fragments a useless feature. Bugfix: Enable Z-ordering for fragments.
Feature request: I'd love to have transparent colors and/or fill patterns for the loop fragment.
3. When applying a solid color fill to a loop fragment and afterwards reverting to the default color fill, all message labels within this fragment preserve the initially set color fill as background font color. This is valid for diagram output using Diagram->SaveToFile, Copy to clipboard, Print Preview, etc.
Closing EA and re-starting fixes the problem, alternatively you can apply white as solid fill for the loop fragment and afterwards revert to default color.
4. Manual resize of sequence message labels to prevent a line-break is not preserved when the label is formatted as bold (when using message sequence numbering). Re-load of the diagram always inserts the same line break after the sequence number on longer message names.
Also when changing the diagram/object font size on an existing diagram EA splits many labels onto two lines - it inserts a line break after the message sequence number.
Feature request: I'd really love a global check-box in the sequence diagram options to enable or disable EA inserting line-breaks into message labels (i.e.: Automatically break labels: Yes or No).
Any hints on how to fix/work-around the problems reported above are also warmly welcome.
best regards
Joachim