REG: Dialog box and action bar buttons missing in texteditor example

When running the quickcontrols2/texteditor example with Qt 6.2.2 or later, the icons on the action bar are missing.

For reference, this is what is looks like with Qt 6.2.1:

In dev branch, the example is additionally broken. If you make a change to the document before quitting, so that you get the "are you sure you want to quit" dialog box, this will be empty with just yes/no buttons and no question.