The problem:
After release of the new editor it is no longer possible to have 2 selections on the page, so term proposal UI doesn't work as it was originally designed. I was supposed to work the following way: select word in source, select word in target (both selections should stay) and click on "Propose term" button, which is currently not possible because once you select a word in source and then select a word in editor - the selection in source disappears and vice versa.

Solution:
To make the UI to work again as it was originally designed we need to create a fake selection in the grid and in editor so the user can again select in segment source and in target and it will be visualized like 2 separate selections.