I did read the post you referred to before deciding to post my suggestion; however as is unfortunately the case in these forums, the original suggestion was hijacked by other posters asking for completely different functionality than requested by the original poster (an edit dialog in this case).
If you fully read the comments, you will find that NI in fact implemented an idea that was completely different from what the original poster requested (NI implemented an edit dialog box instead of the ability to collapse lengthy string constants to an Icon). The original suggestion to provide the ability to display a string constant as an icon on the block diagram was never implemented, yet NI marked the suggestion as completed.
Based on that error on NI’s part, I decided to post my suggestion, which while very similar also includes additional functionality that the other suggestion does not. Specifically:
Right-click menu to convert the string constant to an icon view
The full string is displayed in the context help window when you mouse over the icon
The full string is displayed in an edit time tip strip if the help window is not open
