Hello, I have a bug with Text Items. When I try delete text in text items I got an error: "Invalid caret position. Please contact the developer, if you can reproduce this problem." And I can reproduce this. Minimal application for reproduce, https://www.dropbox.com/s/l3zdwz2zcjwxcng/SRV1.zip?dl=0
First of all write something in first item, then go to the end of the first item and press backspace. That's all you got an error.
It's not allowed to modify text or to make any other changes in document inside OnItemTextEdit event. This event is designed for modifying tag and style (by assigning new values to the parameters) depending on changes in text.
In OnChange, check GetItemText. If it was changed, use SetItemTextEd to modify the second item (set some boolean flag while calling SetItemTextEd to prevent infinite recursion, because SetItemTextEd calls OnChange too)