For more details see related issue.

The problem:
Sometimes editor produces deletions or insertions of the same user not as a single tag, but as a sequence of tags. This is not a bug, but the behavior of the trackchanges component as word can be deleted character by character in different time etc. Editor doesn't condence such changes to preserve actual history of editing.
BUT it produces inconveniences on accept/reject changes. Let's imaging a sentence "Hello world" which was deleted character by character from the start and end so first "H" is deleted, then cursor is moved to the end and "d" is deleted, then cursor is moved to the start and "e" is deleted, then "l", "l", "r" and so on. So as a result we have a sequence of del tags containing a single letter each "H""e""l""l""o"" ""w""o""r""l""d"
Now if we want to accept or reject such track change we have to do it 10 times for each deletion. That is indeed inconvenient.

Solution:
Still condencing changes is not an option because of history. So we need to condence changes from the same user when performing an accept/reject action. Only same type of changes are condenced, e.g. if deletions is followed by an insertion from the same user and we perform accept/reject on deletion - only deletions standing in a row should be condenced.