When you set a stylesheet for your QGroupBox do it like this:
QGroupBox{color: red;}
This way your QTreeWidget will ignore this stylesheet.
Pregunta
How to change the color of every text in QTreeWidget (item text, name of column)?
In fact, I have a QTreeWidget inside a GroupBox and when I have modified the styleSheet of my GroupBox, this was inherited in the QTreeWidget. So, I have modified the styleSheet in the QTreeWidget with color: rgb(0, 0, 0);
, but when I execute the application, the color is the same as the GroupBox and not the stylesheet of QTreeWidget (whereas it is modified in the designer).
Solución
When you set a stylesheet for your QGroupBox do it like this:
QGroupBox{color: red;}
This way your QTreeWidget will ignore this stylesheet.
Otros consejos
YOu could try using QTreeWIdgetItem:SetForeground
or to set the background you could use
item->setBackground(column, QBrush());
qsetheaders sets the headers for the columns in a QtreeWidget