Bug: Sometimes copy/paste works incorrectly

[obreey]

1 Run N++
2 Press New
3 Type some text
4 Highlight some text and copy it
5 Press right button of mouse - I see that “paste” text is bold (in menu)
6 Open Pbrush and copy some part of image
7 Return in N++
8 Press right button of mouse on free white zone

Result: “paste” text is bold (in menu), but if press on it - nothing dooing
ps similarly it reproduced for case, when buffer has a text in him - but in menu “paste” text is not bold

ps* this bug is not reproduced in the notepad (standard windows program)