Original report
observed in Firefox at least.
When I insert something (a macro or an image or an emoticon etc)in the Editor, rather often the editor positions itself to the wrong place. Sometimes even to the top.
Very annoying on long pages.
It also happens when I try to copy some text by moving the mouse over. The highlighted text is no longer highlighed, and the curser jumps to some other place, usually at the top of the editor buffer.

How to reproduce?
Create a page with enough content so that the editor will have the vertical scrollbar present. Scroll down to the ~middle of the page and in a new line add a panel macro. The editor will jump and the newly inserted panel macro will be at the very bottom of the editor.

Tested the behavior with Firefox 19 under Windows and Linux.