Hi, any news about this?
I have the same problem since some weeks and it is very irritating. It is independent from the keyboard, the computer and the database connection. It occurs only in PL/SQL Developer (7.1.5.1398). All my other applications accept the CTRL-C key combination properly. It seems not to be a timing problem. It even occurs if I hold the two keys pressed for two seconds or longer. It is impossible to predict if the data is in the clipboard or not. "Copy" from the editor's context menu works without any problem (but I do not intend to learn this method).

Regards Frank