Strange treeview behaviour: strikeout text only if bold - ruby

Question

I need to show some treeview item text striked out text into a QT treeview from Ruby.
After some reading on QT documentation and much coding, I found that only when rendering font in bold, also the strikeout was rendered.
So I wonder, where I'm doing wrong?
This is the code to achive the result shown above. Note as I set strikeout for every even row item.
I'm using Ruby 1.8.7 and Qt 4.6.2 and qt4ruby 4.4.3-6 on Mandriva Linux.
require 'Qt4'
require 'date'
class MyStandardItem < Qt::StandardItem
def initialize(str = nil)
super str
end
def data(role = Qt::UserRole + 1)
return super(role) unless role == Qt::FontRole
ret_val = Qt::Font.new()
#parameters for "fromString":font family, pointSizeF, pixelSize, QFont::StyleHint, QFont::Weight, QFont::Style, underline, strikeOut, fixedPitch, rawMode
ret_val.fromString "sans serif,-1,-1,0,0,0,0,0,0,0"
case role
when Qt::FontRole
ret_val.setStrikeOut(true) if (index.row % 2) == 0
if index.column == 1
ret_val.weight = Qt::Font.Bold
else
ret_val.weight = Qt::Font.Normal
end
return Qt::Variant.fromValue(ret_val)
end
return ret_val
end
end
Qt::Application.new(ARGV) do
treeview = Qt::TreeView.new do
model = Qt::StandardItemModel.new self
head = [MyStandardItem.new "Qt v. #{Qt.version}"]
head << MyStandardItem.new("Ruby v. #{VERSION}")
head << MyStandardItem.new("Qt4Ruby v. 4.4.3-6 (Mandriva)")
model.append_row head
(1..10).each do |i|
col0 = MyStandardItem.new 'some text'
col0.check_state = ((i % 3) == 0)? Qt.Checked : Qt.Unchecked
col0.checkable = true
col0.editable= false
col1 = MyStandardItem.new "line ##{i}"
col2 = MyStandardItem.new((Date.today + i).strftime '%d/%m/%y')
model.append_row [col0, col1, col2]
end
self.model = model
show
end
exec
end

Answer 1

Eventually I find an hackish trick to overcome this problem. Playing around after reading again the enum QFont::Weight description I tried to set
ret_val.weight = 51 # Qt::Font.Normal value is 50
instead of
ret_val.weight = Qt::Font.Normal
and magically the normal text appears striked out!
Maybe this strange behaviour is due to a bug on QT?