Unified appearance of comments and history

Here is my second try. It's not committed. Please check out the screenshots.

In some cases it takes more space than the original history. This is mostly because of the header for each change set and because the formatting of long text fields, comment and reason for change is preserved.

However, because the changed attributes are highlighted, it is much easier to visually scan the history  for specific changes, like User-assignments or Status-changes.
Mick, I think that was the use case that was important for you, right?

What is (also) important for me, although, is that I see the full picture at one glance.
That means I want to see *what* was changed (Attribute values) right beside *why* it was changed (comment or the reason for change).

In b21 'what' and 'why' are distributed over two tabs - Comments and History. 
The 'why' is hard to read in the History-Tab, because comment and reason for change have lost their formatting, the reason for change is stuffed into a thin column and long comments are cut of after a couple of characters. The 'what' is missing entirely in the Comments-tab.
So I'm often switching between the Comments-tab and the History-tab to get a full picture of an issue.
Even if I'm only interested in the 'why', I have to switch the tabs, because I can never be sure where the 'why' is stored, in the comment or the reason for change. 

So my final proposal is:
Merge the History and the Comments into one single Tab.
Merge the comment and the reason for change into one single construct - the comment.
Add a switch to the merged tab to display either comments or changes or both.
This would make the feature more flexible and still more convenient and simpler.

Ronny