When I right click to copy some text NP++ deselects the whole selected text. It happens on some php files. I m using 6.5.1
This is likely caused by the DSpellCheck plugin. You can either disable it or a new version has been very recently released here which fixes the issue.
Yes, once I disable Dspellcheck plugin, I can select and right click now. Also I m not seeing any update for that plugin in plugin manager list.