I created 2 separate plugins and was trying to do a simple text transfer
between a view in one plugin and a view in the 2nd plugin. Even though
TextTransfer was an accepted type in the target the icon remained as the
"do not enter" one. I tried to use the PluginTransfer (converting the
string into bytes) mechanism, by implementing the dropActions extension
point and using the PluginDropAdaptor. I got the same behaviour. I've
posted my problem up on the RCP newsgroup under the title "Drag and Drop
between separate plugins." I'm on Win XP Professional. I've also added to
Bugzilla Bug 31840, however that one seems to have been logged a year ago.