There's an unexpected behavior with outlining.
My text is "/* abc\r\n". Which gives me "/* abc" on line 1, and an empty line 2.
I call AddNode in my OutliningSource using
AddNode(new TextRange(0, 7), definition)
Where my definition's DefaultCollapsedContent is "/* abc ...", and 7 is the last offset of the whole editor.
The resulting outlining starts and ends on line 1, where I would expect it to start on line 1 and end on line 2 where the last offset is, after the terminating character.