force redraw of every graphicsitem

[Morea]

I'm having a little problem with redrawing in a graphicsview/scene.
If I scroll to another position of the scene, there are some graphicsitems that are not redrawn.
See the picture. There you can see how the boxes are redrawn, but the lines with the integers on are not always drawn, 4 of them are just started, but not finished.

The integers are QGraphicsTextItems that has a customized paint() function that draws a line beneth the integer.

I'm not sure how to make it do a proper redraw of the scene.