Select buffer (mouse clipboard) replaced when editor is opened or undo operation performed

When I open the RTE I lose my select buffer which gets replaced with the content of the editor window. If I hit Ctrl+Z for undo, the selection buffer also gets replaced. For example I have some URL in the buffer, but perform some operation with the editor and trying to paste that with the middle mouse button this ruins the page I'm editing. Usually undo fixes the problem but it is still annoying to remember to always check my clipboard before pasting...

I see same on the official Jive web site trying to create a document.