Example: undoframework. The background is not displayed

Hello everyone!

Standard examples directory: %Qt5_15_2_DIR%/examples/widgets/tools/undoframework/
Resources contain a texture for the background: cross.png

 Small line width in cross.png file - 2px (original image size 100x101 px).

But in the file mainwindow.cpp line 74: 

QBrush pixmapBrush(QPixmap(":/images/cross.png").scaled(30, 30));

scaled k=0.3 and then the line width is less than 1px.
The background is not displayed.
I changed the scale or thickness of the lines in the cross.png and everything works.

Please add changes to fix a small issue.
Best regards, Nikita.  

nnikellspb@gmail.com