Document Viewer example: Button under Help tab named "about documentviewer" opens wrong pop-up message (pop-up message of button named "about Qt")

Steps to Reproduce:

1. Open Document Viewer Example
2. Go to Help tab in the menu bar
3. Select "about documentviewer"
4. Then select "about Qt"

Actual Result:

Pop-up messages in both is the same and that of "about Qt"

Expected Result:

"about documentviewer" should open pop-up message of "about documentviewer" only

Reproducibility: 100%