QTableWidget QTableWidgetItem

[TheKedge]

Hello all,
sorry, I couldn't find exactly what I was looking for prevoius threads.
I want to change the color of a header of a column in a QTableWidget (to show that the column is 'active'). The column header is double clicked and I get a slot called in which I do this:

item = tableWidget->horizontalHeaderItem ( logicalIndex );
item->setBackgroundColor(ChannelEnabled);

item = tableWidget->horizontalHeaderItem ( logicalIndex );
item->setBackgroundColor(ChannelEnabled);

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There is no colour change to be seen. I can colour any other item in the table this way, but not those from the headers. What do I need to do?

Another thing...
the signal QTableWidget::itemDoubleClicked ( QTableWidgetItem * /*item*/ )
gets called on double click on any cell, except those in the headers.

thanks
Kev