For the RB project someone asked me to write an autosizing and autocompleting memobox. Currently the ‘To field’ is implemented as an ‘autocompleting’ combobox: well, typically this combobox was written by myself too. When implementing that combobox I already warned people that this (Windows) control had its limitations. I think the limit is 255 characters. Maybe more, but it wouldn’t be able to show too many e-mail addresses. Hence why one would use the properties dialog.
To make a long story short, the code has been merged with the main sources and now only rests the testing.