I've occasionally come across examples of edit controls that have a special indicator to assist the user, like so:
and I'd like to be able to implement similar in my own code.
The screen-scrap is actually from the property editor for the TIBQuery Sql property and isn't quite what I'm after (otherwise I'd just look in the IBX code) because it disappears as soon as the user types anything. There are others where the indicator moves so as to keep its place as the user types something, but doesn't replace the caret, otherwise I'd just do that.
So my question is, how to implement a special indicator of the type I've tried to describe, that can be positioned and turned on/off in code? The simplest thing I could think of would be to somehow temporarily add a special glyph to the edit control's character set, but I have no idea how to do that, nor how to colour it differently than the control's text content.