As mentioned in previous posts, we're working very hard on the SyntaxEditor for WPF core editing capabilities.  One area that we've been working in this week is advanced selections such as block selections.

Block selections are where you create a rectangle of selection instead of the normal "snaking" variety of selection.

As you can see from the screenshot above, we have block selection working already in SyntaxEditor for WPF.  And it even supports embedded right-to-left text properly!  Although the screenshot's selection looks a bit strange, that actually is the correct way to do a block selection when encountering right-to-left text.

We're making a very concerted effort to ensure that SyntaxEditor for WPF supports any culture.