I found something today that can help you to answer others users. My problem is not only with PL/SQLDeveloper like I Thougth. That happends in others application, the point is de Copy is working but with TEXT ONLY. I detect that because in EXCEL I couldnt copy a formula, buy it copy the value (text). I look on internet a some page say something about the one java update. I did some test and for know when I open Internet Explorer (or Mozilla or Google Chrome) that problem with copy happened, and when I closed them the copy work fine again.