While debugging it works, but while running it doesn't (Font.Size)

[renatoab]

I need to format the font of the title of the axis on a chart.
I'm using the following code:

with ActiveChart.Axes(xlCategory).AxisTitle
.AutoScaleFont = True
.Font.Name = "Verdana"
.Font.FontStyle = "Negrito"
.Font.Size = 7
end with

When I'm debugging the program, everything works, but when the program is running, the instruction ".Font.Size = 7" doesn't work. It only works if I type, for example, ".Font.Size = .Font.Size * 7 / 4.5", but sometimes I want to set it 7 and it doesn't equal 4.5 previously.
I only want to set a constant size.

Does anyone understand what is happening?