If you have opened two documents side by side and try to copy a text from one document to the other, then the focus switch takes about a second in the new version 7.0.1. So you have to wait till the focus switches to the desired document, otherwise the text will be pasted in the previous document.

If you look at the "Opened Documents" panel when you click on a document to focus it, you will see when the document got the focus.

In version 7.0.0 the document switch was nearly instandly.